The hows and whys of vermicomposting

If you’re looking for a productive and child-friendly summer project, this just might be it.

The Latin word “vermi” means worm, and vermicomposting is the process of using worms to create compost. It’s a small-scale recycling process that converts kitchen waste to “garden gold.” Most horticulturalists consider worm compost to be the best soil amendment, since it’s full of beneficial microorganisms and a long list of nutrients essential to plant growth and development.

The final product of the vermicomposting process is a crumbly, rich, dark brown, earthy material. A thin layer of this compost can be used to top-dress the soil of potted plants. It can be worked into garden soil to improve its texture and nutrient content. And it’s especially useful in the vegetable garden, where it helps feed food-producing plants and encourages the development of healthy roots.

Here’s how to get started.

The worms

Red worms or red wigglers (Eisenia foetida)—often sold as bait—are the best species to use for vermicomposting. In their natural environment, they feed on organic matter that accumulates on the soil surface, and they’re content to live in crowded conditions with frequent disruptions (like feeding and harvesting). Other common worm species aren’t suitable for vermicomposting. The night crawler—often used for bait—doesn’t thrive in captivity, nor does the common earthworm, since they both need plenty of soil, room to wander, and cool temperatures to survive and thrive. 

A worm bin is typically started with about one pound of red worms (roughly 1,000), but it can be started with less than that, as long as the bin isn’t initially overloaded with food. Commercial worm farms and local bait shops are good sources of red worms.

Red wigglers in worm bin bedding material.  (Photo courtesy of Andrea Ikeda)

The worm bin

There are many fancy, commercially produced, and expensive worm bins, but it’s simple and more fun to create your own.

The basic requirements for a well-functioning, easy-to-maintain bin: (1) it should be shallow, with a depth of no more than 12 inches; (2) it shouldn’t hold too much moisture; (3) it should have ventilation; and (4) it should be portable. Various vermicomposting resources have different recommendations, so do a bit of investigation to figure out your own preferences and needs, which are partly related to your volume of usable kitchen waste.

For a small-scale worm bin, a lidded, opaque (not clear-sided) plastic container works well. A sturdy, wooden box with a hinged or removable lid can also work, especially for a large outdoor worm box. Worms like a dark environment since their skin is light-sensitive, so a closed container is essential for their comfort and for pest control.

Vermicomposting guides recommend drilling ventilation and drainage holes in a worm box, the first for air circulation, and the second to prevent excessive moisture build-up. Drainage holes do complicate indoor storage, however, and it’s possible to do without.

The location

A dark, indoor, out-of-the-way place—under the kitchen sink, in a laundry room, inside an unused cabinet, or in an insulated garage—works best as a location for worm boxes. “Pet” worms are happiest with relatively consistent temperatures between 55 and 75°F and a minimum of disturbance. (I once tried maintaining a worm box outdoors, and that experiment failed miserably; in my yard, it was too difficult to keep a consistently cool temperature, and the wriggly little decomposers cooked in the summer heat.)

The bedding

Bedding is the material used to fill and refill the worm bin as needed. It serves several purposes, acting as a refuge where worms can shelter and breed, a moisture control agent, and a backup source of food if plant scraps are scarce.

If you subscribe to the print edition of The Record, you have a head start on creating a worm box. Newspapers that use plant-based, non-toxic inks are one of the best and most readily available sources of bedding material. They’re very easy to tear into narrow strips, they hold moisture well, and they decompose readily. (However, don’t use the slick, full-color advertising inserts.)

Other suitable bedding materials are shredded, uncontaminated, corrugated cardboard (minus any tape or non-biodegradable elements such as wax); coconut coir; plain shredded paper without coatings or chemicals (not magazines, cereal boxes, or other packages); burlap cloth; and shredded leaves.

The bedding material should be loose and slightly moist, like a damp sponge. Fill the box to the top with bedding, and replenish it as it settles and breaks down. 

The worm food

Yes—Raw plant matter (apple cores, banana and carrot peels, vegetable trimmings, wilted lettuce leaves, etc.); plain cooked vegetables; crushed eggshells; cooked rice/grains in small quantities; and dead or wilted leaves from non-toxic houseplants all make good food for red worms. So does that mushy bag of greens that sat for too long in the refrigerator (minus the plastic, of course).

No—Pungent plants such as onions and garlic; meat or dairy products; oily foods; pet waste; or vegetable matter that’s been sauced, dressed, or seasoned. It’s also best to avoid citrus; it contains the chemical limonene, which is toxic to worms, and it can make the bin environment too acidic.

It helps to chop food into small pieces before adding it to the bin. Worms don’t have teeth, so their food must be soft or in pieces tiny enough to swallow. They can eat their own weight every five to seven days. Add a handful of clean sand, coffee grounds (used or fresh), or other gritty material to the box too; worms will swallow it and store it in their gizzards to help grind up the food. Slowly but surely, the worms will covert scraps into compost.

Food scraps should be buried at least one inch deep in the bedding, and preferably underneath it. This discourages potential pests such as fruit flies. Don’t add too much food at once, and monitor your bin to ensure that worms have adequate but not excessive meals.

Worm bin with newspaper-strip bedding pulled aside, showing newly added kitchen scraps (top), and decomposing scraps 5 days later (bottom). (Bin recommendations and photos courtesy of Andrea Ikeda)

The harvest

The worms’ digestive systems break down the food scraps, and the by-product—called “worm castings”—is the end goal of the vermicomposting process. In less delicate terms, it’s worm poop. It looks just like rich, dark, crumbly soil, it doesn’t stink, and it’s an incredibly nutrient-rich, organic soil additive.

There are two simple ways to harvest home-created worm compost. The easiest process is from within the bin. Using close-fitting gloves, move all the food scraps and remaining bedding to one end of the bin, leaving the underlying worm compost exposed. Over the next few weeks, put food in the end with bedding, to encourage the worms to migrate to that side, then remove the worm-free finished compost from the other end, picking out and saving any leftover worms. Spread out the remaining material, add new food and bedding, then repeat the process in another few weeks.

The “cone method” is also easy. Remove a few large handfuls of castings to a portable surface (the box lid works well) and shape them into a cone. Move it to a sunny area for a few minutes. After the worms dig to the bottom to avoid the bright light, harvest the compost from the top of the cone and return the remaining compost and worms to the bin.

A more labor-intensive way to collect worm castings is to empty the entire contents of the bin onto a large plastic sheet. Wearing gloves, carefully pick out the worms, any remaining food scraps, and bedding remnants and return them to the box. What’s left behind will be the finished worm compost. Return some of the compost to the bin, add more food, and top off with fresh bedding to start the process anew.

Other notes

For my current worm bin, I used a 10-gallon plastic container without drainage holes, and drilled a series of closely spaced, 1/8-inch ventilation holes around the top. (This is a smaller diameter than usually recommended, but I’ve had better luck with smaller, more numerous holes.) I also use dry newspaper strips when topping off the already-damp contents of the bin. These measures, plus occasionally loosening the castings, keeps the moisture level under control.

Involving kids in vermicomposting will help them learn about the natural environment, recycling, and caring for living things. Teach them to handle the worms sparingly and gently, and encourage them (and possibly yourself) to overcome any squeamishness!

A healthy, productive worm box shouldn’t have an objectionable odor; it should have a fresh, earthy smell that usually isn’t noticeable unless the box is opened. Therefore, having it in or near the kitchen shouldn’t be a problem, and that makes it easily accessible for regular worm feedings.

If you see little capsules that resemble tiny lemons in your worm box, that’s good! Those are worm egg cases; they range in color from bright yellow to brownish, and each contains from two to twenty worms. They’re a sign that your system is functioning well, and you’ll soon have lots of tiny worms populating your bin.

Other little critters might also inhabit your box, but that’s not necessarily a bad thing. If you see miniscule, whitish insects, those are springtails, another species that aids in decomposition. I have those in my box, and I also have pillbugs, which I intentionally introduced since they help break down food matter into pieces small enough for the worms to ingest. Neither of these have escaped the box or caused any problems. Outdoor worm boxes can attract many other small inhabitants as well, but most are simply part of the natural ecosystem.

Fruit flies and ants, however, are unwelcome pests. They can be discouraged by keeping the worm box filled to the top with bedding, by using only recommended food matter, and by occasionally and gently stirring the contents at the bottom of the box.

Vermicomposting resources

  • The book “Worms Eat My Garbage,” by Mary Appelhof (1936-2005). First published in 1993, it was updated by Joanne Olszewski in 2017 for a 35th anniversary edition.
  • UCCE Master Gardeners of San Joaquin County website, “Composting with Worms”
  • The California Department of Resources Recycling and Recovery (CalRecycle) “Vermicomposting” webpage (Their cute little brochure/bookmark called Worms, downloadable from this website, is what got me interested in vermicomposting many years ago.)
  • North Carolina State Extension’s website “Vermicomposting for Households”

If you’re interested in seeing a commercial worm farming operation, plan a future, when-safe visit to P.J. Dunn Working Red Worms in the nearby city of Galt; it’s the closest worm farm to San Joaquin County. Call in advance to ensure that they have worms and worm compost ready for sale, or possibly even arrange for a group tour.

For gardening-related questions, call the UC Master Gardener office at 209-953-6112, or visit our website.

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Helpful resources for gardeners and non-gardeners alike

In one way or another, COVID-19 has been a dominant influence in our lives these past few months, and like it or not, it will continue to be for the foreseeable future. And even if you’ve “had it up to here” with coronavirus news, please read on for the sake of those you care about.

There are still so many unknowns about the novel coronavirus. Can an effective vaccine be developed? Are previously exposed people vulnerable to reinfection by new viral strains? Are sudden new cases of inflammatory diseases in children tied to viral exposure? Over time, scientific investigations will help answer these questions and relieve some of the current uncertainties.

The vast majority of us will apparently escape the most serious health consequences of this pandemic, but within our circle of family, friends, and acquaintances, we all know someone who’s highly vulnerable to severe or even deadly symptoms. That’s why the importance of science-based information can’t be underestimated. That’s also why I’d like to share some helpful and informative resources with my fellow San Joaquin County residents.

Part of the U.C. Master Gardener Program’s mission statement is “To extend research-based knowledge and information on home horticulture, pest management, and sustainable landscape practices to the residents of California […].” University of California, Agriculture and Natural Resources (UCANR) is the umbrella organization for our state’s Master Gardener program, and they now have a webpage dedicated to “Coronavirus and COVID-19”—https://ucanr.edu/Coronavirus_and_COVID-19/.

Some of the many resource categories on UCANR’s “Coronavirus and COVOD-19” webpage (Image courtesy of UCANR)

This UCANR website is divided into several sections: agriculture; food, water, and nutrition; youth development; gardening; exploring your environment; and health and wellness. It’s truly a one-stop-shop of information for the general public, not just for those with gardening on the brain. Some of the available information is specifically virus-related, but other resources are simply helpful for developing and maintaining healthy lifestyles.

Here’s a small sampling of the helpful guidance you can find on this informative site (with the relevant section name in parentheses):

  • “How to Stay Food Secure and Eat Well Despite COVID-19” (Food, Water, and Nutrition)—This flyer includes basic health tips and links to various organizational websites related to local food initiatives, food safety and health, and much more.
  • “COVID-19 Safety Guidelines for Farm Stands” (Agriculture)—This link includes guideline for roadside produce stands and large-format, printable signs for posting at agricultural sites open to the public.
  • “Guidance On The Safe Usage of Open Spaces During COVID-19” (Health and Wellness)—This one-page flyer has basic safety guidelines and links to various public resource agency websites regarding outdoor access.
  • “4-H Healthy Living Activity Guide” (Youth Development)—This 18-page guide is packed full of valuable guidance and fun, age-appropriate activities for children. It’s a wonderful source of inspiring, educational ideas that you can use to keep your kids, grandkids, or students engaged and learning while sheltering at home. A sampling of the contents: building a first aid kit; reducing stress through mindfulness; simple science experiments; and many easy and nutritious recipes.
  •  “Composting Is Good for Your Garden and the Environment”(Gardening)—This informative Master Gardener tip sheet discussed the basics and benefits of backyard composting. This could be an excellent new spring/summer activity for anyone with a bit of space and extra at-home time on their hands. (Note: Even if you don’t have a yard, it’s possible to use the technique of vermicomposting to create your own compost; more about that next topic week.)
  • Other Miscellaneous Resources—While I haven’t yet finished exploring UCANR’s coronavirus website, there are quite a few items that have captured my interest.  The Health and Wellness section includes two mask-making patterns from the University of Florida Department of Anesthesiology that “have been found to be as, or more, effective than the N95 mask.” The Agriculture section includes a practical guide to the Coronavirus Aid, Relief, and Economic Security Act; a resource guide for immigrants in California; and a page called “COVID-19 Infection Prevention for Agricultural Employers and Employees.” The Exploring Your Environment section has links to the UC California Naturalist program; the Cornell Lab of Ornithology (for those interested in citizen science and bird observation); and the nature journaling website of John Muir Laws. (I’ve been fortunate enough to attend one of his out-on-the-trail workshops; he’s a very talented artist and wonderful teacher.) And there’s so much more….

May the information on the UCANR website help you stay safe and well!

For gardening-related questions, call the UC Master Gardener office at 209-953-6112, or visit our websitehttp://sjmastergardeners.ucanr.edu/.

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The tastiest tomato to plant this spring.

Tomatoes come in lots of sizes and colors as there are 7500 cultivars.

It is time to think about getting vegetables planted for delicious summer meals and for next winter too, if you have enough to freeze or can. Many homeowners are reduced to small back yards so having a large garden may not be possible, but room for a few tomatoes, peppers, zucchini or eggplants are often doable—provided there is 6-8 hours of sunshine. According to a national poll, 26 percent of all US households have a vegetable garden with the tomato the most popular crop. Bell peppers rank a distant second.
Amazingly there are 7500 varieties of tomatoes. There are red ones, yellow ones, green ones, black ones; little cherries and large two pound slicers and everything in between. There are so many seeds and so little time to explore this great variety of tomatoes. Here is a bit of garden trivia. The tomato was classified by our Supreme Court as a vegetable in 1893 even though botanically it is a fruit. Tennessee, Arkansas and Ohio have all rebelled and have declared the tomato there state fruit.
I used to have a large garden area which permitted me to experiment a lot with a variety of heirloom tomatoes and peppers to see which ones would do well and were tasty. I would save seeds from the heirlooms I liked for future plantings, and although I now have less room, I still like to grow a variety of vegetables. This year I am planting 18 varieties of tomatoes and perhaps 12 varieties of peppers and 4 eggplants.
I have grown plants for our Linden Garden Club plant sale for several years (this year’s sale was canceled due to the coronavirus). One of the most popular tomatoes each year is ‘Sungold’ a hybrid cherry tomato that is the tomato candy of the garden. Some customers only want red tomatoes and some are more adventurous and willing to try something yellow with names like ‘Azoychka’ or ‘Golden Jubilee’ or one that is bicolor, yellow and red, like ‘Kellogg’s Breakfast’. These are heirloom tomatoes which are open pollenated seeds from plants that are over 50 years old. Heirlooms have become popular with tomato enthusiasts who have become disaffected with standard supermarket faire which is often designed for ease of shipping and long shelf-life.
Tomatoes aficionados look for tomatoes with reputations for good taste and that is one criterion that should be paramount for tomato lovers: see:  https://www.nytimes.com/1997/08/20/garden/the-tomato-singing-its-siren-

Purple Cherokee is an heirloom that wins a lot of tasting contest.

song.html. ‘Cherokee Purple’ is one such tomato that wins a lot of tasting contests and another is ‘Brandywine’. While neither of these plants is high yielding—their good taste is worth the growing.
There are some with reputations for both taste and high yields. Years ago I bought a book by Dr. Carolyn Male ‘100 Heirloom Tomatoes for the American Garden’. I searched the book and picked out the tomatoes that were most productive and tasty and grew them as well as some recommended by the Seed Saver’s
Exchange, a non-profit seed bank organization which started in the 1970s when Diane Ott Whealy wanted to preserve her grandfather’s favorite ‘German Pink’ tomato for posterity.
I discovered: ‘Azoychka’, ‘Druzba’,‘Soldacki’, ‘Bulgarian 7’, ‘Thessaloniki’, ‘Italian Heirloom’, ‘Kellogg’s Breakfast’, ‘Redfield Beauty’, ‘Black Krim’, ‘Black from Tula’, ‘Box Car Willey’, ‘Big Rainbow’, ‘Marizol Gold’, ‘Mortgage Lifter’, ‘Gold Medal’ and ‘Paul Robeson’ among others. How I have enjoyed growing and eating these wonderful tomatoes! They may not be as disease resistant as some of the hybrid tomatoes like ‘Ace 55’, ‘Early Girl’, ‘Big Beef’ and ’Celebrity’, but I haven’t had a disease problem with heirlooms.
There is often a story behind some of these tomatoes that add interest. For example, ‘Mortgage Lifter’ was originally named ‘Radiator Shop Charlie’s Mortgage Lifter’. It was developed by ‘Charlie’ Byles of Logan, West Virginia in the 1930s and was so named because Mr. Byles owned a radiator repair shop, and through marketing of his popular tomato, he was able to lift the mortgage on his house in a mere six years.

German Pink heirloom is one that helped launch the Seed Saver’s Exchange.

Druzba is an heirloom from Bulgaria.

The ‘Paul Robeson’ tomato also has a story. Paul Robeson was a black athlete, opera star and actor who got fed up with segregation in the United States and was sympathetic to the Soviet Union in the 1950s. Russian tomato breeders named this tomato to honor him. The ‘Box Car Willie’ tomato was named after a singer with the Grand Ole Opry whose real name was Lecil Travis Martin. His stage name lives on and you can enjoy this heirloom and others. Happy tomato gardening!

Tomatoes are easily put up for winter fare.


If you have a gardening related question you can contact the UC Master Gardeners at 209-953-6112. More information can be found on our website: http://sjmastergardeners.ucanr.edu/CONTACT_US/.

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Spring is busting out all over.

Are you feeling homebound after the edict by our Governor to stay home? Here is something that will help reduce your anxiety level and deal with the threat posed by the Coronavirus. Enjoy some gardening which is a well-known stress reducer. I have not been feeling anxious about the virus because I have been busy gardening.  Last year we installed a new septic tank and as a result there was a lot of lawn missing and the old lawn was a bit spotty.  Last week we had sod installed in our back yard so now we have a new green lawn that makes our landscape beautiful and complete. We also added 12 yards of mulch to the vegetable garden and orchard areas after putting down landscape fabric. This will keep the weeds at bay and make gardening much easier.

It is a joy to see so many blooming flowers this time of year. Many trees are blooming; tulip trees, Bradford pears, flowering plum and lots of Western and Eastern redbuds. Last year I removed a sweetgum (Liquidamber styracciflua) from my landscape as the gumballs it dropped were such a nuisance and the tree was not well developed. Although there is now a sweetgum that has been bred that doesn’t produce gumballs, I decided that I would replace that tree with two redbuds.

Freesias are a cheerful spring container bulb.

I have missed the redbuds at my previous home, Redbud Farm, where there were 13 large Eastern redbuds in the landscape. Hence I purchased and planted two grafted redbuds that are ‘Appalachian Red’ cultivars of Cercis Canadensis. ‘Appalachian Red’ has blooms of a deep pink tone than the usual lighter pink of redbuds. They came as very small trees, but I hope they will grow quickly to provide shade and blooms.

Spring is a good time to take stock of your landscape and see what you might have room to add to it for spring enjoyment. With the coronavirus keeping us all at home it is not a shortage of time that would keep us from doing this. Do you have a few blank spots?  Are there some tired plants that could be replaced? I decided that one thing I am missing that I used to enjoy are peonies, so I am thinking about finding room to fit one or two into my landscape. I don’t have a lot of room, because I bought my new home from a fellow Master Gardener who had done a great job of landscaping. It is positively beautiful and is one of the many features we enjoy at our new home.

In the front yard, there is a mostly native plant garden and the two backyard borders feature roses, a lilac, Azaleas, Narcissus, Chinese ground orchid (Bletilla striata), three Chinese fringe bushes (Lorapetalum Chinensis), several daylilies and lots of white flowers: Cala Lilies, (Zantedeschia aethiopica), Candytuft (Iberis semperiverns), an unnamed white Camellia, several white Lenten Roses (Helleborus orientalis), and two Spirea shrubs in full bloom. If you have Spirea it is good to prune them after they bloom to keep them healthy and to foster new growth for next year’s blooms. Spirea bloom on new wood so rejuvenating the plant by pruning will keep them blooming fully.

There are also three bluebell varieties in the border and I had a devil of a time figuring out what they were. There are a lot of plants named bluebells and they are in disparate genera. One is the Portuguese squill (Scylla Peruviana). Here is a little garden trivia for you. It is a native of the Western Mediterranean but was named Peruviana because Peru was the name of the ship that brought the specimen to the taxonomist but the ship was not from Peru as it turns out. After a lot of studying on my computer, I identified the two other bluebells as Spanish bluebells (Hyacinthoides hispanica) and Siberian squill (Scilla siberica).

 I also planted about 300 Narcissus in the last two years and have enjoyed their blooms this spring. I also have 5 pots full of Freesias and I don’t know how or why I have so many, but I am enjoying all the color they bring to my deck this spring. Another garden activity might be to consider planting containers of herbs that you need for your summer cuisine or what flowers you want to foster for summer blooms. I have already planted parsley, culinary sage and basil in containers. I have also been planting gladiolus in a raised bed for early summer bouquets.

Other garden activities may soon include planting tomatoes, peppers, zucchini, beans, melons, corn, and annual flowers like zinnias, marigolds and chrysanthemums. Enjoy being homebound, plan for ever more beautiful gardens and stay healthy.

 If you have a gardening related question you can contact the UC Master Gardeners at 209-953-6112. More information can be found on our website:  http://sjmastergardeners.ucanr.edu/CONTACT_US/.

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Vegetable gardening in the days of COVID-19, and beyond

An extended period of home isolation might be necessary in the near future to minimize the rapid spread and devastating consequences of the new coronavirus pandemic.

Last week, I recommended vegetable gardening as a way to cope with the stress of social distancing and as a source of healthy food and safe outdoor activity. That topic deserves more attention, given the growing concerns about COVID-19.

In this time of uncertainty, growing fresh annual vegetables and melons at home might be anything from a productive form of outdoor activity to a much-needed source of nutrition for your family and for others in need. Growing food at home is very satisfying, and it also helps reduce trips to the grocery store.

Whether you have a large backyard or just a sunny balcony, it’s possible to grow even a small number of food-producing plants. The basic requirements are good soil, water, a source of nutrition (worm castings, compost, or commercial vegetable fertilizers), and direct sun exposure of at least 6 to 8 hours each day.

Japanese eggplants interplanted with marigolds for pest control and a splash of color. (Photo by Kathy Ikeda)

If you’ve never grown vegetables at home before, or would like to become better at it, here are some excellent resources:

  • San Joaquin Master Gardeners’ “Home Vegetable Gardening” website: http://sjmastergardeners.ucanr.edu/Home_Vegetable_Gardening/. This page has links to a locally appropriate and easy-to-read vegetable planting guide, a University of California publication entitled “Vegetable Gardening Basics,” information on growing vegetables in containers, and much more.
  • The University of California’s Integrated Pest Management (UC IPM) webpage for vegetables and melons: http://ipm.ucanr.edu/PMG/GARDEN/veggies.html. This site is organized by type of plant—beans, carrots, corn, peppers, squash, tomatoes, and so on. Each page provides not only pest control tips for each plant, but also a whole range of valuable cultural care information: planting, watering, fertilizing, harvesting and storage, and much more.
  • What’s Growing On, the blog by San Joaquin Master Gardeners (SJMGs): http://blogs.esanjoaquin.com/gardening/. Most of our past articles are accessible on this website, as a public service provided by SJMGs and The Record, and many are about vegetable gardening and related topics.

Seeds are one way to start growing vegetables now, in preparation for summer or fall harvests. Some food plants—such as beans, carrots, corn, melons, squash—are ideal for April planting from seed, and they should be planted in the ground where they are to grow. This is called “direct seeding,” and it’s the easiest planting method. 

Other vegetable seeds can be started indoors or in a greenhouse. This method is usually used with tomatoes, peppers, and eggplants, which can be started indoors from seed as early as January and February (when temperatures are too cold outside for proper seed germination and growth). It’s a bit late in the season to start these seeds now, but you can give it a try. 

Leftover plastic containers from earlier plant purchases—especially six-packs and 4-inch pots—work well for starting vegetable seeds. Improvised seed-starting trays can also be made out of rigid plastic produce containers, the ones pre-punched with ventilation holes; their lids help retain some humidity, which helps keep soil moist. Before starting seeds in old or pre-used containers, sterilize them by submerging them in a mild bleach solution (one part bleach to nine parts water), rinse them with lukewarm water, and allow them to dry before filling them with a seed-starting mix. Then, plant seeds according to the instruction on the packets. 

After your vegetable seeds sprout and grow to an adequate size (a minimum of two sets of mature leaves), they can be transplanted into the garden after a “hardening off” period. This means gradually exposing them to ever-increasing increments of direct sun exposure over a period of about two weeks.  

You can help support our local economy by buying seeds or seedlings from area nurseries and garden centers. Call in advance to verify their hours of business—since they might be modified or even closed due to virus-related concerns—and to check their availability of vegetable seeds or seedlings. Or, order seeds online and have them delivered to your home.

Vegetable plants—especially root vegetables like carrots, beets, and potatoes—prefer loose, deep soil that’s rich in organic matter. If you have heavy clay or sandy soil, amend it with compost to help assure your vegetable plants’ health and vigor.

Once your plants start growing in earnest, make sure they get adequate water. Vegetables prefer consistently moist soil, and tomatoes and peppers are particularly susceptible to damage from inconsistent watering. Also, most vegetable plants don’t like water on their leaves (it encourages fungal growth), so avoid overhead sprinklers and use a ground-level hose or drip irrigation. 

Another growing tip: avoid using pesticides. Home vegetable gardening is the easiest way to obtain fresh produce free of chemical contamination, and most common pests can be eliminated with non-toxic methods. Chewing damage from caterpillars, such as cabbage loopers and tomato hornworms, can be minimized by inspecting plants and picking off any invaders by hand. Aphids, which like to congregate on and suck juices from the leaves of many vegetables, can simply be sprayed off with a strong stream of water. Earwigs can be caught at night in rolled-up newspaper, then disposed of in the morning.

Once your plants start bearing their much-awaited edibles, it’s time to enjoy! Even non-traditional parts of some vegetable plants can be eaten. Beets, Brussels sprouts, and pea greens are a few favorite examples in our family. The leaves of these plants aren’t usually seen in grocery stores, but they’re perfectly edible. Once washed, they can be julienned and added to a salad, or chopped and lightly sautéed with olive oil and some seasonings for a delicious side dish. But be cautious. The leaves of some vegetables contain toxic compounds and should not be eaten, so be sure to check a reputable source before eating atypical parts of a plant.

A basket full of unique and decorative “Michael Pollan” tomatoes, named after the well-known author (Photo by Kathy Ikeda)

If you end up having a larger harvest than you can use, you can preserve many kinds of vegetables by canning them. An important note: home canning must be done in a way that eliminates the possibility of botulism, a serious and often fatal illness. It’s caused by a species of bacteria (Clostridium botulinum) that produces an extremely potent toxin; contamination can be prevented by proper sterilization and heating processes.  If you have canning-related questions, you can find information here:

Finally, this is a perfect time to share the bounty of your garden. Give some vegetables or fruits to your house-bound, elderly neighbors. Donate your excess produce to local food banks, senior centers, and homeless shelters. Maybe even support a local, independent restaurant, by helping reduce their costs for purchasing fresh vegetables. (Call any organization or business first—before dropping off fresh foods—to see if your produce will meet their needs, and to avoid potential waste or other problems.) Use your personal vegetable gardening project to strengthen our community, both now and for the long term.

Wishing you good health and happy growing!

For gardening-related questions, call the UC Master Gardener office at 209-953-6112, or visit our websitehttp://sjmastergardeners.ucanr.edu/.

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The value of gardens and gardening in trying times

This is truly an unprecedented period in the history of our country and our world. The sudden development and rapid spread of the COVID-19 coronavirus is upending lives around the planet, and our normal lives and customary routines have been put on hold for the foreseeable future.

This column is supposed to be garden-related, but before I delve into that topic, it’s important to acknowledge my fellow human beings’ stress and grief. To anyone struggling with isolation, loss of job or income, disrupted school schedules, or other difficult circumstances, I wish you strength and the hope that your needs will be soon be met. To those who are ill with the novel coronavirus, I wish you a quick and complete recovery. To all the medical professionals who are providing virus testing and caring for infected patients, and to others whose important and ongoing work puts them in harm’s way, I send wishes for your good health and a message of profound gratitude. And to anyone who has lost a loved one as a result of this pandemic, my deepest and most heartfelt sympathies.

Whatever your circumstances are in this moment, my hope is that gardens and gardening can help in some way.

Elephant sculptures amid beautiful blooms at the Clovis Botanical Garden, February 2020. Their raised trunks are symbols of good fortune, a timely wish for all. (Photo by Kathy Ikeda)

Gardens and natural environments are very therapeutic. Simply being outdoors amidst fresh air, sunshine, and greenery can reduce stress, alleviate depression, lower blood pressure, and increase our bodies’ production of vitamin D. Caring for plants is a wonderful source of physical activity, and it also stimulates the mind. Self-care is particularly important now, and gardening is one cheap and easy way to fulfill part of that need.

Rather than thinking of “yard work” as a necessary drudgery, try focusing on its health-giving benefits. Any stay-at-home time spent pruning, weeding, or planting is helping keep you fit and strong. And, if your time and energy level allows, why not try a fun and rewarding mini-project? If you have some favorite perennial plants, try propagating them by taking stem cuttings, treating them with rooting hormone, and planting them in moist, sterilized potting mix. If you have an unused/underutilized area or an unwanted patch of grass, start planning now to replace it in fall with California natives; this will help support local pollinators and restore a bit of natural habitat. Or, plant a tree or shrub to honor a loved one.

Vegetable gardening is yet another rewarding and productive pursuit during this time of recommended “cocooning.” You might recall that residents of the U.S. and other countries were encouraged to plant their own Victory Gardens during World Wars I and II and other periods of national crisis and solidarity. Now—as then—vegetable gardens can provide healthy physical activity, a morale boost, and an inexpensive source of nourishment in the days and weeks to come. March and April are ideal months to plant seeds of summer crops such as beans, carrots, corn, eggplant, melons, peppers, squash, and tomatoes. For those with school-age children, this is an opportunity to teach them where their plant-based food comes from and how to grow it. Consider sharing share seeds and harvests with your loved ones and neighbors while developing a healthy, long-term habit of growing your own food. You can find locally appropriate vegetable gardening resources at http://sjmastergardeners.ucanr.edu/Home_Vegetable_Gardening/.

While spending time inside your home, houseplants can be a source of joy. Their greenery beautifies rooms, and in some circumstances they help purify and oxygenate indoor air. Ornamental plants are truly a form of horticultural therapy; they’ve been proven to aid in recovery from sickness, and having plants nearby helps improve human memory, concentration, and productivity. This is an excellent time to learn more about caring for each of your indoor plants; to repot them with fresh planting mix; to give them a spring feeding with worm castings, compost, or fertilizer; or to gently bathe them and clean their leaves of accumulated dust.

Outdoor exercise is another great coping strategy, and it’s still allowed under current statewide COVID-19 guidelines. If you live near a public park or garden, plan a short visit for some physical activity and relaxation. However, do so cautiously, and remember to keep a safe distance from others so that you don’t expose yourself or them to unnecessary risk. Stay close to home, and be sure to check ahead of time about open hours and restrictions. Two small and close-at-hand public gardens are the native plant garden at the Oak Grove Nature Center and the Learning Landscape outside the San Joaquin Master Gardener office.

I hope that you can use gardens and gardening to help maintain your health in the coming days and weeks, within the limitations of prudent social distancing. Please be sure to follow any current and developing state and federal COVID-19 recommendations and orders, to ensure the safety of your family, friends, and the community at large. We’re all in this together.

As an additional public service, please refer to these reputable sources of information regarding COVID-19:

For gardening-related questions, call the UC Master Gardener office at 209-953-6112, or visit our website:http://sjmastergardeners.ucanr.edu/.

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Growing Dahlias is hard work but very rewarding.

I have grown dahlias for a lot of years and I am still learning how to be successful at propagating this plant from tubers. Dahlias come in various nuances of colors, sizes, and forms and they bloom starting in June continuing to November. Last year I had about 150 Dahlias. They are a bit perplexing and difficult at times, but the rewards are so great that the effort to deal with these cantankerous tubers is worth it.
One good thing about living in California, you don’t have to dig your dahlia tubers to keep them from freezing like my mother used to do where I grew up in New Jersey. My mother only had a few dahlias and perhaps digging a few and storing them in the cellar each year was enough of a workout.
I am hard-pressed to dig all the dahlias that I grow. Last year I dug all of them, but this year I dug only half. It is a chore to wash off the black adobe clay from the tubers, label and store them in wood shavings until this spring when they will be divided to replant or give away. Dahlias tubers left in the ground over the winter are well established and know when to start growing and they bloom sooner than newly planted tubers. If you like early blooms, and who doesn’t leave some in the ground. The downside of not digging them is that some may rot if the winter is particularly wet which is not the case this winter. Hence I am hoping that the four rows I didn’t dig will be blooming early.
Tubers should be planted 2-3 feet apart with 4 feet between rows to allow access. They will need to be staked and tied as they grow, so best to plant the stake at the same time that the tuber is planted so the tuber is not impaled by the stake if done later. Tomato cages can also be used to confine the plants. I like to mix compost into the planting hole which enhances growth without chemical fertilizers. Just planted tubers should not be watered heavily but once plants are growing about 1 inch of water per week is good. I use a drip system with 2 GPH emitters and water for an hour every other day or about 6 gallons per plant per week.
Unfortunately, there are always pests lurking to ruin your dahlia garden. When the first shoots appear they are food for snails, slugs, and earwigs. These pests can be thwarted by using snail and slug bait. If you have pets the best bait contains iron phosphate which unlike metaldehyde baits will not harm your pets. You can also deplete the population by hunting them by flashlight at night. Earwigs can be thwarted by placing some diatomaceous earth in a ring around the young shoots or they can be trapped using tuna fish cans or cat food cans with ¼ inch of oil preferably fish oil in the bottom with the cans buried at ground level. It is also a good idea to deny them hiding places beneath boards or mulch if possible.
Later in the season, the pests are thrips and spider mites. When you want to enjoy the blooms these critters want to enjoy the dahlia leaves. I found that spraying the foliage with water helps control their abundance as mites don’t like moist conditions and they along with thrips can get washed off. Insecticidal soaps and Neem oil solutions can also be used. It is good to stay on top of this or the plants will suffer and blooms will be less too. It is also good to keep a sticky trap in the garden to monitor for thrips abundance and keep on top of it. For more information on pest control see: http://ipm.ucanr.edu/.
Keep flowers deadheaded or preferably your vases full. To encourage larger blooms it is good to disbud the two side buds and leave the main bud. It also a good idea to head cut the new plant at 12 inches to encourage early-branching which will result in more blooms later. It is also good to thin older well-established dahlias if there are many weak shoots they should be removed to enhance energy going to the main stems.
More info and videos on dividing and storing Dahlias is at Swan Island Dahlias at: http://www.dahlias.com. Happy dahlia gardening.

If you have a gardening related question you can contact the UC Master Gardeners at 209-953-6112. More information can be found on our website: http://sjmastergardeners.ucanr.edu/CONTACT_US/.

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Zinnias are great to grow for summer blooms.

Zinnias are the work horses of the cutting flower garden. They are easy to grow and have a short time from planting to bloom time. They attract bees, butterflies and hummingbirds so are a great addition to a pollinator-attracting garden. I have done some flower show judging at fairs and the first time that I judged zinnias at the Big Fair in Fresno I was amazed at the variety of zinnias as I had only known a few cultivars of Zinnia elegans. There are other species but insufficient room here to describe them all.

Zinnias require rich, well-drained soil in full sun. Zinnias do best when kept evenly moist, and you can feed them with compost or a balanced fertilizer every few weeks for best flower production. For extended bloom, deadhead plants throughout the season or just keep all your vases full. Remove unsightly leaves to prevent the spread of disease and to keep plants looking healthy.

They evolved in the warm climate of Mexico so they are heat and drought tolerant but not frost tolerant and should not be set out before frost time is past. They are best planted after night temperatures reach above 50 degrees F. You can get a head start on the blooming season by starting the seeds indoors or in a greenhouse 4-6 weeks before planting in the garden. Seeds should be planted about 3 inches apart. A sunny windowsill will work and germination takes about 6 days.

Seeds can also be sown directly in the garden; 1⁄2 inch deep with 2- to 3-inch spacing in rows 12 inches apart in well-worked, fertile garden soil in full sun. Gently firm the soil and then keep it evenly moist while awaiting germination. When seedlings become large enough to handle, thin them to 10 to 12 inches apart. In the garden, it is good to provide for air circulation to minimize infection with powdery mildew. Zinnias come in a wide range of colors (except blue) from lime green, red, yellow, pink, orange to white. You can usually purchase a mix of colors or a one-color selection. They also come in a multitude of forms and sizes as described below. Hence they can fit a lot of garden spots from containers to front and back borders.

Petite: ‘Thumbelina’ zinnias generally don’t grow more than 4-6 inches and come in all the colors of the rainbow in a compact, versatile plant that is good in border fronts or containers. ‘Pepito’ and ‘Button Box’ seeds produce dwarf plants that are 10 inches tall. ‘Profusion’ zinnia series is a hybrid of (Zinnia angustifolia x Z. elegans) and it is a low growing choice especially for containers or mass planting. The two-inch flowers are single or semi-double and daisy-formed which cover 12 to 15-inch mounding plants. This All-America Selections award-winning series has cultivars that come in shades of orange, cherry, white, and apricot, all of which partner well with other colorful plants. Profusion zinnias are highly disease resistant and require little maintenance because they are self-cleaning; dropping their blossoms after they fade.

Small: ‘Lilliput’ are 18-24 inches with blooms that are small, round bauble-like that add interest and texture to your garden, or flower arrangements.  ‘Pulcino’ produces 18-24 inch, bushy plants that are early and prolific flowering with double and semi-double blooms. It is also known as ‘Cut and Come Again’ zinnia. 

Medium: ‘Scabiosa’ has finely textured blooms on plant 30 inches tall. ‘State Fair’ has 5-6 inch, double-flowered blooms and a bounty of colors on 30-inch robust plants that are great for cutting and enjoying in the vase.  ‘Peppermint Stick’ zinnias grow to 30 inches and are uniquely striped like a holiday peppermint. ‘Oklahoma’ series are 30-40 inches and can be obtained in several individual colors from white, pink, salmon, scarlet and gold. The flowers are 1.5 to 2.5 inches in diameter.

Large:California Giants’ are 48 inches with flowers 5 inches across; a very productive, large plant for the cutting garden. ‘Benary’s Giant’ zinnia is an award-winning variety producing large 4-5 inch diameter fully double flowers on sturdy 40-48 inch branching stems. ‘Dahlia Flowered’ zinnia grows to 40 inches and has fully doubled flowers 4-5 inches in diameter with tightly packed petals that bend downward slightly at the ends. They were developed in 1919; so definitely an heirloom. ‘Gift’ is an heirloom zinnia that is a Russian contribution with all red color and 36 inches tall with 3-4 inch flowers—a favorite of mine. Happy zinnia gardening!

If you have a gardening related question you can contact the UC Master Gardeners at 209-953-6112. More information can be found on our website:  http://sjmastergardeners.ucanr.edu/CONTACT_US/.    

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It’s time to plan for spring garden events

Spring is a busy time for garden-related happenings in San Joaquin and neighboring counties. There’s something happening nearly every weekend between now and summer, and with so many events to choose from, there are plentiful opportunities for fun and enriching outings. Consider taking advantage of these upcoming events to expand your knowledge, buy new water-wise plants, view beautiful and inspirational gardens, and more:

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Classes by UCCE Master Gardeners of San Joaquin County

When:      Various dates

Where:     Various locations

Website:   http://sjmastergardeners.ucanr.edu/

Your local Master Gardeners have a wonderful series of free classes planned for spring this year. Dates and locations vary to encourage attendance throughout the county. See the Calendar of Events on the right side of our website’s home page, and click on “Show More” for additional details. Upcoming classes include “All About Tomatoes” (February 25), “Creating Your Summer Vegetable Garden” (March 9), “Planning Your Summer Vegetable Garden” (March 16), and “Summer Vegetable Garden Above the Ground” (March 24). Space is limited; call 209-953-6100 to reserve a space.

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2020 Smart Gardening Conference

When:       Saturday, March 14 from 8:15 a.m. to 4:10 p.m.

Where:     Robert J. Cabral Agricultural Center

                  2101 E. Earhart Ave., Stockton

Website:   http://ucanr.edu/sgc20

This conference by the UCCE Master Gardeners of San Joaquin County features a choice of 20 garden-related presentations, to be held in two morning and two afternoon sessions. This year’s featured speaker is “Plant Lady” Marlene Simon, horticulturalist and garden columnist for the Sacramento Bee. A few presentations will be given by the local Master Food Preservers. More details to come in next week’s article!

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Fair Oaks Horticulture Center Open Garden Days

When:       Saturday, March 14 from 9:00 a.m. to noon

                  Wednesday, April 15 from 9:00 a.m. to noon

                  Saturday, May 9 from 9 a.m. to noon

Where:     11549 Fair Oaks Boulevard, Fair Oaks

Website:   http://sacmg.ucanr.edu/Fair_Oaks_Horticulture_Center/Workshop_Schedule/

This center is the demonstration garden for the UCCE Master Gardeners of Sacramento County, and it boasts a water-efficient landscape, a composting area, an irrigation display, and an expansive edible garden. Each monthly event features several different, free mini-demonstrations by knowledgeable presenters. These are rain-or-shine, outdoor events.

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UC Davis Arboretum Plant Sales

When:       Saturday, March 14 from 9:00 a.m. to 11:00 a.m. (members only)

                  Saturday, March 14 from 11:00 a.m. to 1:00 p.m. (public sale)

                  Saturday, April 4 from 9:00 a.m. to 1:00 p.m. (public sale)

                  Sunday, April 26 from 9:00 a.m. to 1:00 p.m. (public sale)

                  Saturday, May 9 from 9:00 a.m. to 1:00 p.m. (public clearance sale)

Where:     UC Davis Arboretum Teaching Nursery

                  Garrod Drive (across from the Veterinary School), UCD campus, Davis 

Website:   https://arboretum.ucdavis.edu/plant-sales

The semi-annual sales at this one-acre nursery feature a huge variety of offerings, including reliable California natives and plants on the Arboretum All-Stars list — those species specifically recommended for planting in the Central Valley. Arrive early for the best selection; these sales attract many visitors. View the plant sale inventory at https://bit.ly/2HxDPNP. Arboretum members (including anyone who joins during the sale) receive a discount on purchases. While you’re in the area, take time to look at the beautiful, water-wise landscaping at the nursery, visit the adjacent Mary Wattis Brown Garden of California Native Plants, or wander the Arboretum pathways along Putah Creek. 

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CNPS Spring Native Plant Sale

When:       Saturday, April 4 from 9:00 a.m. to 2:00 p.m.

Where:     Elderberry Farms Native Plant Nursery

                  2140 Chase Drive, Rancho Cordova

Website:   https://www.sacvalleycnps.org/native-plant-gardening/plant-sales          

This semi-annual sale by the Sacramento Valley Chapter of the California Native Plant Society (CNPS) features a wide variety of California native perennials, shrubs, and trees. CNPS’s spring sale is held at Soil Born Farms on the American River Parkway, which features attractive native plants gardens and wildlife-friendly hedgerows (an example of conservation-based agriculture). Admission is free; proceeds from this event support CNPS’s educational and conservation work.

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Gardens Gone Native

When:       Saturday, April 25 from 9:30 a.m. to 4:00 p.m.

Where:     Gardens throughout Sacramento and Yolo Counties

Website:   https://www.sacvalleycnps.org/native-plant-gardening/garden-tour

This free, inspiring, self-guided tour by Sacramento CNPS features different residential landscapes planted at least 50% with Northern California native plants. (Many gardens also include compatible water-wise plants from Mediterranean regions.) Online registration is required. A list of garden locations will be provided to registered participants closer to the tour date; every participant selects their own route and which gardens to visit. Learn how to support native pollinators and wildlife, reduce water and pesticide use, and encourage beneficial insects while meeting enthusiastic tour hosts.

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San Joaquin Master Gardener Open Garden Day and Plant Sale

When:       Saturday, April 18 from 9:00 a.m. to noon

Where:     Robert J. Cabral Agricultural Center

                  2101 E. Earhart Ave., Stockton

This event showcases the UCCE Learning Landscape, a demonstration garden created and maintained by the UCCE Master Gardeners of San Joaquin County. Explore the different sections of the garden (Mediterranean, California native, pollinator, edible, and more) and get gardening-related advice from our many on-site volunteers. Offerings at the plant sale will include vegetable seedlings, culinary herbs, a variety of perennial plants, some California native plants, and a nice selection of easy-care succulents. A plant list will be posted online closer to the date of the event.

A colorful scene from a past regional garden tour, with a whimsical sculpture and many beautiful California native plants. (Photo courtesy of Kathy Ikeda)
 

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Bringing Back the Natives Garden Tour

When:       Sunday, May 3 from 10:00 a.m. to 5:00 p.m.

Where:     Various locations in Alameda and Contra Costa Counties

Website:   https://www.bringingbackthenatives.net/garden-tour

This is another self-guided garden tour. Pre-registration is required, a $10 fee is charged for the garden guide, and a donation of $15 per person is suggested to help cover event costs. Garden access will only be granted with the tickets included in the paid garden guide.

This year’s tour showcases 35 private gardens and several East Bay California native nurseries. Garden sites for this tour are divided into two categories: “Bayside Cities” and “Inland Cities.” Be sure to visit gardens in the latter category if you’re looking for inspiration, since the weather pattern in inland Bay Area cities most closely matches the hot-summer climate in our area. Visit the website to register, view the tour flyer, and access photos and other helpful information. 

For gardening-related questions, call the UC Master Gardener office at 209-953-6112, or visit our website: http://sjmastergardeners.ucanr.edu/.

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Reveling in warmth, hoping for cold

I enjoy mild winter weather as much as the next person. It’s so refreshing to emerge from the house on an unseasonably warm and dry day and bask in the sun’s rays while catching up on garden chores. 

People tend to think of cold weather as inconvenient at best and damaging at worst. Frigid days and nights lead to chilly hands and feet, higher heating bills, and other nuisances. In our gardens, predictions of overnight frost or deep freezes mean that we need to protect our cold-sensitive citrus trees, tender perennial plants, and outdoor pipes from damage.

Cold days might be unwelcome, but the horticulturalist in me yearns for more of them. Why, you might ask?

Cold temperatures are an essential element of the Northern California climate, and they’re actually beneficial to our native plants, many favorite perennials, and orchards. The natural yearly progression from warm weather to cold and back again triggers biochemical responses in plants that regulate their growth cycles. Cold weather is one signal that plants heed to begin their winter rest period, called “dormancy.” Like people, plants need their sleep.

The dormant period begins in the fall when the day length shortens and temperatures decrease. These changes prompt deciduous plants to drop their leaves and produce growth-inhibiting hormones. Those hormones prevent the plants from “leafing out” during the winter, even if there are periods of unseasonably warm weather. This chemical mechanism protects the plants by delaying the growth of tender new leaves, which would be damaged if the weather suddenly turned cold again. The dormant period is broken only when the plant experiences a cold spell of sufficient length to break down the hormones. This process is often referred to as chilling or vernalization. 

Such chilling is also essential to our local agricultural production. Temperate fruit and nut trees — those species that go dormant in winter but can’t survive extreme cold — need a specific, cumulative number of chill hours where temperatures are between 32 and 45 degrees Fahrenheit. Without adequate and consistent cold weather, their productivity can suffer tremendously: leaf bud growth and development will be delayed, flower buds will drop or be poorly formed, flowering can be prolonged (thus making blooms more susceptible to diseases), and fruit set will be reduced.

Some common orchard trees have high chill requirements. Depending on the variety, walnut trees need 500 to 700 chill hours to break dormancy. The ever-popular Bing cherry needs 900 chill hours to effectively bloom and set fruit. And the Bartlett pear, which comprises roughly 75% of the world’s pear production, needs a whopping 1500 chill hours each winter! On the other hand, almonds, figs, olives, pecans, and persimmons have relatively low chill needs. To read more about this topic, see the University of California’s online publication, The California Backyard Orchard, “Tree Selection” (http://homeorchard.ucanr.edu/The_Big_Picture/Tree_Selection/#chill)

A Manteca almond orchard in full and glorious bloom. (Photo by Kathy Ikeda)

Chill hours are one set of data recorded throughout the state by the California Irrigation Management Information System (CIMIS). Our local CIMIS station is located in Manteca, and during the 2018-2019 winter season — measured from the first day of November to the last day in February— it recorded 924 chill hours. During the unseasonably warm winter of 2014-2015, we had only 723 chill hours.

As of February 9 this year, San Joaquin County has an accumulated winter total of 881 chill hours. That might sound adequate, but other factors come into play as well. When cold weather is interrupted by periods of several consecutive days of warm, sunny weather, the cumulative seasonal chilling requirement can increase. Spring-like weather during winter essentially offsets some of the prior chill hours. According to the Master Gardener Handbook, “Cloudy or foggy weather that maintains temperatures below about 60°F during the day and 45°F at night is often necessary in parts of California to achieve adequate chilling hours.”

For the sake of our plants, we should rejoice in a normal season of cold winter weather.

With the certainty of warming trends due to climate change, home orchardists might want to plan ahead when selecting new fruit or nut trees. Consider planting types with naturally low chill needs, or buy fruit varieties specifically bred to have “low chill” requirements — 300 hour or less of temperatures below 45 degrees F. (Low-chill cherry cultivars have only been developed in the last couple decades.)

If we do get more near- to below-freezing temperatures this year, here are a few tips on caring for cold-tender plants:

  • Move sensitive potted plants indoors or to a protected area (under a patio cover or overhang, or against a wall that’s warmed by the sun).
  • Keep in-ground and potted plants well watered, because dry plants are more susceptible to cold damage.
  • Drape old-style Christmas lights over citrus trees and other tender plants. Unlike the newer styles of bulbs, old incandescent bulbs generate enough heat to provide a measure of protection from the cold.
  • If plants are damaged by frost, don’t remove any dead or dying growth until the risk of freezing weather is past, because the damaged leaves and stems will help insulate and protect the still healthy parts of the plant.
  • Once it’s safe, prune away all damaged parts. Dead growth will be spongy or limp, and if the bark is gently scraped away from a part of a dead stem, the color below will be black or brown. On the other hand, living tissue will be firm, and a thin layer of green will appear below the bark.
  • Avoid pruning live plants too early or heavily, because that could stimulate them to produce new, cold-sensitive growth. 

For gardening-related questions, call the UC Master Gardener office at 209-953-6112, or visit our websitehttp://sjmastergardeners.ucanr.edu/.

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