Improving Soil Health With Cover Crops

This taprooted Daikon radish does double duty by breaking up heavy soils and being delicious.

Cover crops are plants grown for the direct benefit of the soil rather than human consumption. They were known in ancient China and India and have been standard practice in many agricultural regions of the world, including colonial America. This changed in the 1940s when our WWII infrastructure was redirected toward the production of fertilizers, pesticides, and other chemicals that replaced traditional land stewardship practices.

In its own way, the “Green Revolution” cushioned humanity from nature’s attempts to sabotage our tomato beds, and it certainly increased global food production. Unfortunately, the environmental and human health costs begged for better solutions. Before long, we saw the return of traditional (but improved) cultural practices such as cover cropping, which offers better living through biology.

Building soil health and fertility are the main reasons for using cover crops, but the benefits don’t stop there. The soil’s many organisms play a major role in plant vitality, and they love cover crops, which they use as food. This recycles important nutrients, particularly nitrogen, back into the soil for future plant use. Over time, the increased biological activity improves soil’s structure, and water and nutrient holding abilities.

Creating balance is another key to healthy soil, which cover crops achieve in several ways. They break up the cycle of pests and diseases that accumulate when plants within the same family (e.g. tomatoes and eggplant or cucumbers and melons) are grown too many times in a row. The habitat cover crops provide is beneficial to a diversity of creatures, preventing any one species from becoming a pest. You even get a natural weed block, as many weed seeds cannot germinate through the thick mat of cover crops.

Selecting your cover crop takes some research, but it’s usually best to choose a mix to counterbalance drawbacks of any given species. At minimum, you should plant legumes (e.g. fava bean, cowpeas) for a quick release of Nitrogen, and grasses (e.g. winter rye) to decompose more slowly, providing a longer-lasting mulch and slower Nitrogen release. Other cover crops to consider are oilseed radishes whose taproots break up heavy, compacted soil, and buckwheat, which establishes quickly, providing rapid weed suppression.

Using cover crops takes some planning, as you will be growing them in place of food crops. They are an excellent alternative to letting soil lie fallow over winter when rains can leach nutrients out of the root zone or cause erosion. Select a site in full sun and sow seeds in September or October. Water until the rains arrive, and then only as needed during winter dry spells. They won’t need any other maintenance until March, when you cut them down in preparation for your food crops. The exact timing depends on how quickly they begin to set flower, which is when you want to kill them.

Tradition calls for tilling cover crop biomass into the soil. For soil microbes, this is like taking a bulldozer to your house and hosting a dinner party the same day: possible, but not conducive to comfort. Bacteria, fungus, worms, and many other organisms feeding on organic matter exist in different strata of the soil, depending on what stage of decomposition their food needs to be in. Some organisms, especially bacteria, are immobile, so disrupting the soil layers moves many to where they won’t be able to access the food they need. If you feel more comfortable incorporating the cover crops into your soil, organisms will eventually repopulate, but try to disturb them as little as possible.

Four to six weeks before planting your food crop, kill the cover crop with a lawn mower, weed whacker, or string trimmer, cutting as close to the ground as possible. Spread the biomass evenly on the ground as a mulch. At planting time, use a mattock to create planting strips. Food crops started from large seeds or transplants work best.

Other benefits of the “no-till” method include keeping weed seeds buried, and saving you a lot of work. As long as you have legumes, the temporary nitrogen deficiency mentioned above should not be an issue. Selecting annual grasses rather than perennials will help ensure they won’t stick around when it comes time to plant your food crops. Finally, be sure to kill cover crops before they set seeds to maximize nutrient recycling and prevent weed problems.

See the Sacramento County Master Gardener website at <> for information on traditional cover crop methods. 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.


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Indoor Plants Help Clean the Air

Spider Plants are great for filtering indoor air pollution

Many people are drawn to the aroma of a new car, a recently varnished cabinet in all its unscratched glory, or “spring fresh”- scented cleaners. We may revel in newness and hygiene, but the smells associated with “fresh and clean” are often due to toxins in a variety of household products. When released into the air, these chemicals become indoor air pollution and have been linked to a variety of illnesses, including nausea, asthma, cancer, and neurological, developmental, and reproductive disorders.

While it’s impossible to eliminate them completely, you can reduce levels by choosing products with fewer toxins, and growing indoor plants to filter some of the harmful volatile organic compounds (VOCs) out of the air. If this seems like horticultural hocus-pocus, worry not; indoor plants have proven their worth in many scientific studies that tested some of the most common VOCs such as formaldehyde (paper products), benzene and toluene (plastics, detergents, glue), and ammonia (cleaners, fertilizers).

To get the most out of your indoor plants’ filtration benefits, it helps to know a few factoids. One of the most important things to know is that the foliage has only a secondary role in the removal of undesirable compounds. Most of the action happens in the soil, called the “potted plant microcosm” by researchers, where VOCs are metabolized into harmless byproducts. Carbon monoxide is also taken up by soil bacteria for their metabolic processes, and by plants to stimulate root growth and seed germination.

Unfortunately for those who lack a green thumb, your dead plant coffins (pots of soil with deceased plants) will not keep this microcosm alive. Plants and soil microbes have a mutually beneficial relationship in which plants provide sugars for soil microbes; microbes, in turn, help plants access more nutrients and water.

Another fact to consider is that some plant-microbe teams are better than others at VOC reduction. Examples of great air-cleansers include Boston Fern (Nephrolepis obliterata), Spider Plant (Chlorophytum comosum), Purple Heart Plant (Tradescantia Pallida), Areca Palm (Dypsis lutescens), and Rubber Plant (Ficus elastica). NASA’s list of clean air plants, created after their seminal research of the late 1980s, is easily found with an internet search and provides more plant ideas.

On the flip side to this biofiltration boon, some potted plant microcosms actually emit VOCs as well. Soil bacteria is responsible for some, so plant selection can help. However, most come from cultural practices, which the plant guardian has more control over. Selecting plant species whose needs match your home environment will prevent a lot of problems, as keeping them healthy will be easier. If necessary, use horticultural oils instead of toxic pesticides to deal with pests. Feed with organic fertilizers instead of synthetics; better yet, choose plants with lower fertilizer needs, and place them outside, if possible, when it’s time to feed so that some of the VOCs are gone when the plant is brought back indoors (some plants do not like being moved, so do your homework first). Choosing clay or ceramic over plastic containers can further reduce VOC emissions.

For more information on caring for indoor plants, check out the SJ County Master Gardener website at If you have a gardening related question you can contact the UC Master Gardeners at 209-953-6112.


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Garden for bounty and health.

Some of the bounty from my garden.

I grew up on a farm and have enjoyed both the outdoors and seeing things grow. As a kid, I would get home from school and take my dog for a hike in the 40 acres woodlot that was part of our farm. This early exposure to nature shaped my later life as an ecologist and biologist. My mother was a talented, excellent gardener and she fostered my love of growing food and flowers.

Recently, gardening projects have been started as a healthy way of connecting children with the environment as schools have added gardening to their curricula. Teaching math and science along with the practical aspects growing food is a hands-on dynamic approach to learning that connects children with soil and plants.

If you google either Gardening or Nature and Health, you will get lots of articles on how being in a natural environment or a garden is good for one’s health. Here are just three examples and excerpts: Why gardening is good for your health -, “Two separate studies that followed people in their 60s and 70s for up to 16 years found, respectively, that those who gardened regularly had a 36% and 47% lower risk of dementia than non-gardeners, even when a range of other health factors were taken into account.”  How Hospital Gardens Help Patients Heal  Scientific American- “ Just  three to five minutes spent looking at views dominated by trees, flowers or water can begin to reduce anger, anxiety and pain and to induce relaxation, according to various studies of healthy people that measured physiological changes in blood pressure, muscle tension, or heart and brain electrical activity.”

Petal Power: Why Is Gardening So Good For Our Mental Health, “when we exercise levels of serotonin and dopamine (hormones that make us feel good) rise and the level of cortisol (a hormone associated with stress), is lowered. It’s true that a session in the garden can leave you dead on your feet, but it can also get rid of excess energy so you sleep better and ultimately feel renewed inside.”

Likewise if you google recidivism rates in prison populations as affected by horticulture and gardening, you will also find many articles touting how gardening has positive effects. Here is what one academic review paper had to say about mental health aspects. “Prison gardening programs were shown to enhance incarcerated individuals’ psychosocial wellbeing in three key ways: 1) increase in self-efficacy and self-worth, 2) decrease in anxiety and depression spectrum symptoms, and 3) reduction in recidivism rates.”

Fortunately I have never had a prison experience, but I have experienced all my life the mental and physical benefits of gardening. There is value in learning early the responsibility of nurturing plants and being connected to other living things. Gardening is also mentally challenging. There is a lot to know and learn about the thousands of plants and seeds available to the gardener today and all the aspects of managing their environments so they prosper. You never run out of learning possibilities and challenges.

Most of our life is spent interacting with other humans, so it is restful to spend time with plants and pets far from the maddening crowds—which works well for me.  About 99 percent of our time on earth as a species was spent in a truly natural environment in small groups of perhaps 40 humans. The age of civilization and living in cities is only one percent of species history and the existence of very large cities has happened just since 1800. As recently as the 1930’s Depression, fifty percent of our population lived on farms growing most of their own food. Presently 63 percent live in urbanized, artificial environments which can be very stressful. Gardens provide a break from the stresses of modern life and a chance to reconnect soil and plants.

Thomas Jefferson said it well in 1813, “I have often thought that if heaven had given me choice of my position and calling, it should have been on a rich spot of earth, well-watered and near a good market for the productions of the garden. No occupation is so delightful to me as the culture of the earth, and no culture comparable to that of the garden. Such a variety of subjects, someone always coming to perfection, the failure of one thing repaired by the success of another, and instead of one harvest a continued one through the year. Under a total want of demand except for our family table, I am still devoted to the garden. But though an old man, I am but a young gardener.”

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:

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Dispelling some garden Myths

The following is a description of common garden myths that gardeners can and should avoid.

  • Drought tolerant plants don’t need water. Well, yes, they do need water in their first year until they become established which will encourage roots to go deep. Once established they become drought tolerant.
  • When it comes to fertilizers and pesticides, if a little is good, twice is better. This myth can raise havoc with your plants and the environment. It is very important to follow the directions when applying chemicals. One of my Master Gardener friends told the story of supplying a relative with a large container of glyphosate (Roundup), enough to last for years. The following year he wanted more because, not reading the directions, he had used it at full strength instead of diluted, which for Super Concentrate Roundup is 3 tablespoons per gallon of water. Since glyphosate has been declared a cancer causing chemical, using more than necessary is unwise to say the least. Oversupplying chemical fertilizer can burn the plant’s roots. Some expert has figured out the right amounts of fertilizers or pesticides to use and has put it on a label—so reading and following label instructions is good for your health and your plant’s health.
  • Add sand to clay soils will loosen up the soil. I was once guilty of believing this one when I lived with black adobe soil in North Stockton. It sounds sensible that sand, which drains well, should help clay soils drain better, but this is not what happens. It creates a compacted mess that is more difficult to till unless so much sand is added that it becomes sandy soil. Adding compost and organic matter is the best way to create better drainage and tilth to heavy clay soils.
  • Egg shells because they have sharp edges repel slugs and snails. This is not a sure fire remedy as snails can crawl over razorblades without harm. Other approaches work better. Bands of dry diatomaceous earth, sawdust or sand around your plants can deter snails better. Wide copper strips on raised beds will also work by apparently giving the snail a shock, but they are a rather expensive cure at the price of copper. Nocturnal hunts with a flashlight or at dawn can eliminate a lot of snails or nearly all of them if you are diligent. If you use snail and slug baits and have safety concerns about wildlife and pets, it is best to use iron phosphate baits which are safer for pets and the environment than meta-aldehyde baits. In all cases, read the label and apply properly.
  • The phosphorus fertilizer myth. Phosphorus may often be limiting in agricultural soils that have been heavily used for production. However, in landscaped, urban soils phosphorus is rarely deficient and the over application of this element can interfere with a plant’s absorption of iron, manganese and zinc, resulting in yellowing of leaves and poor plant health. Phosphorus is generally stable in the soil and unlike nitrogen, does not readily leach out. Rarely is it necessary to add bone meal or high phosphorus fertilizers when landscape planting.
  • Treating pruning wounds with paint, tar or grafting compound. This actually does more harm than good because the natural callousing process that the tree invokes to reduce pathogens infecting the wound is inhibited. Thus, it is important to make clean cuts with clean tools and let the tree or shrub heal on its own. If heavy pruning is to be done, it is best done in late winter which reduces the risks of wound infection.
  • Dig deep holes when planting trees or shrubs and the plants will be more stable. Actually, dig a wide hole and not a deep one. A deep hole with loose material under the plant can cause it to settle deeper than it was when grown. This is especially bad for grafted trees where the graft union ends up located at ground level or below. It is especially critical for dwarfing-rootstock fruit trees to be planted with the scion or top part kept at the depth it was in the nursery. If planted too deep, the scion part may grow its own roots and hence lose the dwarfing characteristics of the rootstock. One exception to this is rose planting in cold climates where the graft union is placed an inch below the surface to help insure winter survival; not a problem in most of California.
  • Fill the planting hole with compost and fertilizer. This would seem like a great idea, but it has the result of not forcing the roots out into the native soil and thus restricts root growth to the nutrient rich medium you added to the hole. This adversely affects the stability of the plant and its ability to access water. For more information on many garden myths, see:  Happy myth-free 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:


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An up-close look at pollen (achoo!)

For many people, pollen is the “p-word”. . . as in, “PLEASE, don’t say that word!” The mere mention of pollen can conjure up runny noses, watery and itchy eyes, and looks of desperation from those with hay fever. Here in the fertile, crop-rich San Joaquin Valley, it’s often said that if you don’t already have allergies, you’ll develop them.

Trees such as oaks, birches, conifers (pines, firs, spruces), and nut crops (walnuts, almonds, pecans) are especially prolific producers of pollen, and they’re ubiquitous in our area. They’re joined by other common pollen-producing plants, including grasses and many of our favorite garden flowers. It’s an allergy sufferer’s nightmare.

Pollen literally means “fine flour” or “mill dust” in Latin. While it’s a health nuisance, it’s also a valuable and necessary evil.

We’re familiar with pollen as that yellowish, powdery-looking stuff that drifts away from trees and other plants in spring and summer, making us miserable as it floats through the air, collects on our cars and homes, and settles in our nostrils. But without pollen, we literally couldn’t survive. The vast majority of plants on Earth depend on pollen for their reproduction, and we in turn depend on plants for food and oxygen.

Pollen is unique to seed-producing plants, which are divided into the flowering plants (Angiosperms) and the cone-bearing plants (Gymnosperms). The pollen-bearing structures of these plants are contained either in the flowers or the cones. More primitive plants such as ferns, fungi, mosses, and horsetails don’t make pollen; instead, they produce spores.

So, what exactly is pollen, anyway?

A clue to pollen’s specific purpose lies in the aforementioned scientific classifications of pollen-producing plants: the suffix –sperm means “seed” in Greek. Pollen is the male vehicle for a seed-forming plant’s sexual reproduction. Each microscopic pollen grain has a hard outer coating that protects the inner contents—two sperm cells and a tube cell—from damage and dehydration.

Plants fall into two categories when it comes to the type of pollination: (1) self-pollinated, or (2) cross-pollinated, where pollen from one plant must transfer to another plant of the same species.

Pollination begins when grains of pollen move from the male part of a plant to the female part of a plant. Pollen transfer can occur in one of two ways: (1) abiotic pollination, where pollen is carried by wind or water (most common in grasses and trees), or (2) the far-more-typical biotic pollination, where a living organism such as a bee, butterfly, moth, wasp, fly, bird, bat, or other animal moves the pollen (most common in non-tree flowering plants).

Once a pollen grain comes in contact with the female part of a plant, it germinates. A pollen tube develops, emerging through a specialized opening in the outer covering then extending toward the structure that holds the egg. The sperm cells then leave the pollen grain and travel through the pollen tube, ending their journey when they reach the egg. Fertilization occurs once the plant’s egg/ovule and sperm cells unite, and that initiates seed development.

Some amazing pollen-related facts about corn: Just one stalk can produce about 18 million pollen grains! The pollen grains land on the ends of the female corn silk; there is one strand of silk attached to each developing kernel. The single-celled pollen tubes that grow from the pollen grains through the silk can be up to a foot long!

Many small members of the animal kingdom depend upon pollen. Honeybees and native bees use protein-rich pollen, either eating it themselves or mixing it with sugary nectar before feeding it to their developing larvae. (Pollen is not used to make honey; honey is regurgitated nectar.) Some beetles—including ladybugs—and many common types of web-weaving spiders also consume pollen as part of their diet.

When seen under a microscope, pollen grains are exquisitely beautiful natural works of art. Their outer coatings are intricately patterned, spiked, or pitted, and different plant species produce their own unique pollen designs. Pollen can be sticky-surfaced or spine-studded so that it’s easily carried on the hair, feathers, or fur of pollinators, or it can be lightweight and aerodynamically crafted to float in a breeze.

False-color scanning electron microscope image of pollen grains from a variety of common plants: sunflower, morning glory, prairie hollyhock, oriental lily, evening primrose and castor bean. (Public domain image from the Dartmouth Electron Microscope Facility)















For more information and a visual treat, read the book Pollen: The Hidden Sexuality of Flowers, or search the Internet for “pollen electron microscopy” to see extraordinary images. And try very hard to appreciate pollen, even as it makes you sneeze.

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


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The Fun and Fascinating Ladybug

Let’s take some time to learn more about one of our much-adored garden inhabitants: the lady beetle or ladybird beetle, commonly referred to as the ladybug.

The name “lady beetle” originated during the Middle Ages, when Catholic farmers prayed for relief from crop-destroying insects. When small beetles arrived and began devouring the pests, it was thought to be an act of the Virgin Mary, and the rescuers were named “Beetles of Our Lady.” The rest is history!

Entomologically speaking, the ladybug isn’t a true bug (those insects belonging to the order Hemiptera). Instead, it’s a member of the order Coleoptera, which means “sheath winged” and includes beetles and weevils. Most Coleopterans are helpful hunters of harmful insects. The specific family to which ladybugs belong is Coccinellidae.

Amazingly, there are nearly 200 species of ladybugs in California. One of the most common in our area and throughout North America is the Convergent Lady Beetle (Hippodamia convergens). The adults of this species have two elytra—the pair of modified wings that forms a hard cover—that are red with black spots; their heads, legs, and antennae are also black in color.

Different ladybug species can vary greatly in appearance. Some ladybugs have orange, yellow, grey, brown, or even black elytra; some have numerous spots, while others are spotless. The common names of ladybugs often reflect the number of spots on their shiny backs: seven-spotted ladybug, twelve-spotted ladybug, and so on. Other names are more interesting. One example is Chilocorus orbus, a native California ladybug with two large red spots on its jet-black elytra; its rather frightening common name is Twice-Stabbed Lady Beetle.

Like butterflies and moths, ladybugs undergo complete metamorphosis, passing through four different life stages: egg, larva, pupa, and adult.

During the spring and summer, a female ladybug lays small clusters of oblong, yellowish-colored eggs. She deposits them near aphid colonies or other pests, so that her “babies” will have a handy source of food when they emerge. A single female can lay up to 1,000 eggs in a single season. The eggs hatch into larvae in about three to five days.

Ladybug larvae are small but fearsome looking, and it’s important to recognize them so as not to squash them in a moment of panic or revulsion! They are usually about 1/4 to 3/8 of an inch long, dark brown to black in color, with bright spots or bands on their bumpy or spiny exoskeletons.

Larval ladybugs are efficient and highly mobile hunters, and they’re more effective predators than adult ladybugs. They use their large mandibles (chewing mouthparts) to feed upon aphids, mealybugs, scale insects, mites, leafhoppers, and other soft-bodied insects. A single larva can consume hundreds to thousands of insects from the time it hatches until it begins to pupate. Once the pupa forms, it takes several days to two weeks before an adult ladybug emerges.

Larva of the Convergent Lady Beetle eating an aphid (Photo by Jack Kelly Clark, UC IPM)

Pupal form of the Convergent Lady Beetle (Photo by Jack Kelly Clark, UC IPM)










It can be tempting to buy a squirming bagful of ladybugs to release at home. It’s certainly entertaining to watch the little critters crawl away, looking like miniature hemispherical hovercrafts. But before you purchase ladybugs, consider these potential pitfalls:

  • Ladybugs should be released in the evening in a location with moisture and plenty of their favorite prey. Without these conditions, they usually fly away.
  • Commercial vendors often collect ladybugs from the wild, while they’re congregating and relatively inactive during the winter. Removing them can negatively affect the ecological balance of an area.
  • Non-native ladybugs can be introduced to areas where they displace native species and become pests themselves. Be careful to purchase local ladybug species.

Rather than buying ladybugs, try attracting them to your garden by creating a welcoming habitat. Adult ladybugs eat nectar and pollen in addition to insects, and they also need places for shelter. Composite flowers (asters, coneflowers, sunflowers, and yarrow) and other flowering plants such as alyssum, penstemon, and milkweed are ladybug favorites, as are edible herbs such as chives, cilantro, and dill. Large grass species, including native deer grass, provide excellent shelter for overwintering congregations of ladybugs.

Convergent Lady Beetles congregating at the U.C. Berkeley Botanical Garden (Photo by Kathy Ikeda)













If you’re fortunate, you might find ladybug eggs, larvae, or pupae in your own yard this summer, and be able to witness another part of this amazing insect’s life cycle.

For a good layperson-friendly guide to ladybugs, check out the “Identifying Ladybugs” page on the website of the Natural History Museum of Los Angeles.

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

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Tune In To Radio Show For Great Garden Tips


"Farmer Fred" hosts two radio programs on Sunday mornings, offering advice on growing healthy gardens that resist pests and reduce chemical use.

Finding garden advice is easy, but scientific research has raised awareness of our impact on the environment, challenging many traditional practices. Accessing and interpreting this information can be difficult; one place to go is the airwaves, where you can listen to California native and long-time gardener Fred Hoffman, known to many as radio personality “Farmer Fred”.

Fred uses a blend of humor and hands-on experience to share his message of earth-friendly gardening practices. His journey began 37 years ago with a dangerous chemical, which is both ironic and more common than you might think. Fred’s dog at the time had fleas, so he covered the backyard with Diazinon, a highly toxic insecticide for household and garden pests (it was made illegal for residential use in 2004). It worked a little too well; the usual buzzing drone of backyard life was soon replaced by an eerie silence, telling of the insect community’s wholesale destruction. This was Fred’s “aha” moment, which so many organic gardeners have after such an experience, when one decides there must be a better way.

You may not like those creepy-crawlies, but annihilating insect communities only causes more problems in the long term. Fred’s determination to find a better way led him to the newly minted University of  California Master Gardener program, where trained volunteers bring research-based knowledge to home gardeners. Fred became a certified Master Gardener in 1981, and has since logged over 8,000 volunteer hours, harnessing his training and a lifetime of personal experience to educate the community about better ways to manage pests.

Fred’s gardening know-how and quirky personality appear on “The KFBK Garden Show”, and “Get Growing With Farmer Fred”, both airing out of Sacramento on Sunday mornings. Fred loves to talk about tomatoes, but like any good talk show host, he covers a wide array of topics: vegetables, fruit trees, roses, ornamentals, succulents (e.g. cactus), irrigation, lawn care, etc. His message is always underscored by one of his favorite mottos: “surf with Mother Nature”. This means favoring plants appropriate for our climate, encouraging a balanced insect community, building healthy soil, and taking other actions to work with, rather than against nature.

Each week Fred invites a guest on to the show to share their expertise. Some are regulars, such as American River College horticulture instructor Debbie Flowers, and soil specialist and organic gardening advocate Steve Zien. Other guests include nursery owners with decades of experience, garden writers, Master Food Preservers (an off-shoot of the MG program), rosarians (rose experts), and people involved in “plant trials” conducted by the University of California, who share the latest in growing beautiful, water-wise plants.

Some of the gardening practices Fred talks about have been around for decades (or centuries), but there is always more to learn. Fred has an announcement segment where he shares information sent to him from various organizations offering classes, workshops, conferences, plant sales, home and garden shows, and other educational or just-for-fun events.

Another important service Fred’s show provides is announcing serious pest threats in the area, and what you can do to help slow the spread. Sometimes it’s as simple as eliminating standing water where mosquitoes might lay their eggs; other times, there are more serious steps such as contacting the Agriculture Commissioner if you spot Asian Citrus Psyllid on your citrus trees. Fred also covers quarantines, which is hardly everyone’s favorite topic, but are important in the protection of the area’s agricultural economy.

Fred has two great websites, one being a supplement to the “Get Growing” radio show (see below), the other a blog entitled “The Farmer Fred Rant®”. Both have great gardening tips for Central Valley residents wishing to improve the health of their garden and the environment. In spite of the blog’s name, there isn’t any real “ranting” going on, just a sprinkle of sass here and there to keep things interesting.

Fred’s two radio shows air back-to-back on Sundays: “The KFBK Garden Show” begins at 8:00am on 93.1FM KFBK, followed by “Get Growing With Farmer Fred”  from 10:00am-12:00pm on 650AM KSTE. For the farmers out there, he also hosts “The KSTE Farm Hour” at 12pm after “Get Growing”. Links to his blog and podcasts can be found at

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.


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Managing Leaffooted Plant Bugs in Your Garden

The Western Leaffooted Plant Bug is a pest of many plants, such as citrus, tomatoes, and pomegranates.

The garden’s bounty is in full swing, offering humans and insect pests a full buffet of goodies to munch on. One such pest of the Leaffooted Plant Bug (LPB), an insect related to the stink bug and lover of both edible and ornamental garden plants. While most veggies and fruit can handle light feeding by the LPB, letting populations get out of control may cause more serious problems.

LPBs are relatively easy to spot. Of the three species commonly found in California gardens, the Western LPB (Leptoglossus zonatus), with its brown, 1-inch long body and white zigzag-patterned back is what you will most likely find amongst your edibles (see photo). The distinguishing feature and namesake of all LPBs are leaf-like enlargements on the hind legs of adults, which serve as weapons in what can best be described as “thumb war” with legs. Females and males use their leafy legs in territorial disputes by waggling threats at each other and delivering beatings. Males attempt to dislodge opponents with a single-legged hook over the thorax, or a double-legged squeeze to the abdomen.

This predilection for knocking each other about does not preclude them from forming aggregations of 5-500 individuals on leaves, stems, and fruits. Adults spend the colder winter months snuggled up in protected areas of the garden. Woodpiles, barns, palm fronds, citrus or juniper trees, tree cracks, and pump house shelters all serve as winter vacation homes. Feeding and mating commence in spring, with their cylindrical, brown eggs laid end-to-end on leaves and stems, hatching into reddish-brown nymphs in about a week. All three stages (egg, nymph, adult) can exist at the same time during the growing season, with females laying an average of 335 eggs in their lifetime.

The Leaffooted Plant Bug feeds by piercing fruits and other plant parts with their long proboscis, sucking the juices out. They are partial to pomegranates, tomatoes, and citrus, but will attack almost anything. Nymphs have short probosces, causing superficial damage only; adults have much longer probosces, getting down to the seeds and excreting an enzyme to liquefy them for easier digestion. Adults feeding on small-sized fruits such as immature tomatoes may cause them to abort. Feeding on larger-sized fruits such as citrus or mature tomatoes may cause surface depressions, discoloration, and reduced “juiciness”. Damage to mature fruits is usually only aesthetic, and will not cause serious problems for the home gardener unless the population is overwhelming your plants. Ornamentals are also subject to LPB feeding, but damage is typically minor, only affecting leaves and stems.

If you have spotted the Leaffooted Plant Bug in your garden, it is best to take care of them when populations are low. The best control method is manual: shake the LPBs out of your plants onto a sheet, dump them into a bucket of soapy water, then dispose of them in your garbage. This technique is most effective under the following conditions: 1) it’s done early in the morning when the adult LPBs are still sluggish and less likely to fly away, 2) the population consists of more (flightless) nymphs than adults, and 3) it is performed on a regular basis, at least 3 times a week to start, until the problem is under control.

Another important management strategy is to reduce their sources of winter food and shelter. Remove as much of their overwintering habitat (see above) as possible; remove or mow down weeds, which supply seeds that feed LPBs in winter and early spring when fruits are unavailable. Applying mulch to the soil surface will help reduce weed populations as well.

Sound like a chore? Unfortunately, the LPB shares the stink bug’s talent for secreting a foul-smelling compound when annoyed, making them undesirable to many potential predators such as birds and other insects. There are a few parasitic wasps and flies that prey on LPBs, and once you get a serious infestation under control, these natural enemies can keep populations in check. Broad-spectrum pesticides can help bring a serious infestation under control if you have mostly nymphs, but this will kill off your pollinators and other beneficials that offer long-term management, so use pesticides only as a last resort. Please note that there are no pesticides available to homeowners for effectively managing adults LPBs.

The UC Division of Agriculture and Natural Resources is researching the Leaffooted Plant Bug’s spread throughout California. You can help by taking a quick, 2-minute survey. Go to their Pests in the Urban Landscape blog at <>. Click on the survey link at the bottom of the June 17th post entitled “Leaffooted Bug” to let them know whether you saw the LPB in your garden and what plants you saw them on. This survey will be up until July 15, 2016.

More information on Leaffooted Plant Bugs can be found on the UC Integrated Pest Management’s website at <>. 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.

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Gardening tips for tomatoes, squash bugs

Tomato season is here and I have heard this complaint several times from gardeners. “My tomato plants are tall and healthy looking, but I don’t have any tomatoes. What might the problem be?”  Well the problem might be that the gardener used too much nitrogen fertilizer and it stimulated lots of vegetative growth to the detriment of fruit set. Generally tomatoes do not need a lot of nitrogen fertilizer.

Another cause of poor tomato fruit set might be lack of phosphorus which is the important nutrient to stimulate fruit set. This is not likely a problem here as valley soil phosphorus is usually adequate. I use two shovels of compost per plant and they do fine as my soil is a fertile clay-loam as are lots of soils in the County. If you have sandy soils fertilizer such as 5-10-10 may be appropriate. You can also mulch with compost.

Another problem might be lack of sun. Tomatoes need about 6 to 8 hours of sunlight each day to set fruit, otherwise spindly fruitless plants. One other cause of poor fruit set can be temperature.  Fruit set is reduced at temperatures greater than 90° F and is optimal in the day time range of 65-80° F and night time range of  59- 68°F. Fruit set is poor at temperatures less than 55° F. If we have a prolonged period of day temperatures over 90 ºF, expect poorer fruit set during that time.

Insufficient water will also cause blossoms to fall off, so another good practice is regular watering and water deep. Tomato roots will go 4 feet deep. I apply water every 3 days for 90 minutes, about 3 gallon per plant using a drip system on a controller. Inconsistent irrigation can cause a calcium imbalance in the plant which results in blossom end rot and a tomato that you won’t be eating. The problem is the watering and not lack of soil calcium. Most soils have sufficient calcium available for plants. Hence, throwing egg shells or other calcium sources at your tomatoes usually won’t help. Overwatering can also cause cracking and splitting.

One of the things I learned as a Master Gardener was the bees actually increase pollination in tomatoes. This was confusing to me because I know that tomatoes are self-pollinating. Apparently, a bee buzzing the flowers enhances the transfer of pollen within the flower. Giving tomato cages a shake as you pass by enhances pollination for the same reason.  I spend a lot of time in the spring making sure the tomatoes stay within the cages, so I give the cage a little shake   as I pull straying vines back into the cage. Stray vines can also be pruned off as well to keep the plant tidy and inside the cage. For more information on tomato growing see:

Squash bugs (Anasa tristis) are widely distributed in North American and a nasty pest of squash and pumpkins. About 4 years ago I thought I had won the battle. I killed all the overwintering bugs so they did not reproduce. For three years afterward, no squash bugs showed up in my zucchini patch.  However, last year I had a few and this year a great many once again, so somehow they found my isolated garden. I have repeated my ‘kill on sight’ approach and here is how I have managed to keep these pests at bay. It requires daily diligence. Monitor your plants and if you see wilting in the morning, you better look for squash bugs or eggs on the stems or under the leaves. Eggs are laid in lines or clusters and are bronze to red in color and about 1/16 inch long. They hatch in about 5-10 days into small grey nymphs. Scraping off the eggs results in death to the eggs because they have no nurturing substrate when they hatch. You can also use duct tape or masking tape to remove eggs and nymphs. Once they hatch successfully it is far more difficult to catch and kill the small nymphs.

To get the adult bugs, I have found that splashing water on the base of the plants will send the bugs climbing up the stems to safety to avoid water and drowning, but instead, they get a quick death squished between my thumb and forefinger. They don’t smell great, but don’t be squeamish if you want zucchini. Boards or wood shingles placed under the plants will also provide a hiding substrate for attracting and collecting them. Squash bugs can cause wilt ‘anasa wilt’ which is thought to be from toxic substances injected by their sucking mouth parts which also remove sap from the plant. For more info:  and  Happy squash bug squashing.

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:

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Protecting Plants from Summer Heat

Scorching days have arrived! All but the hardiest of us wilt when outdoor temperatures hit the 90s and 100s, and we seek refuge in air-conditioned places or in water-cooled outdoor areas. Plants don’t have that luxury; they’re literally rooted where they are, and they sometimes need our help to deal with the Central Valley sunlight and heat.

Summer weather can damage plants by stripping them of the moisture they need or by exposing them to more heat or light than they’re adapted to handle. Higher than usual air temperatures, intense light, and overheated or too-dry soil can harm a plant’s leaves, stems, and roots. Wind can further worsen the effects of hot air.

Like humans, plants rely on water partly to cool themselves: we sweat, plants “transpire.” Transpiration is the process by which plants absorb water through their roots, move this water upward through the part of their vascular system called xylem, then lose this water through tiny pores called stomata on the leaf surfaces. The transpiration rate rises in hot temperatures; a plant’s water loss generally doubles with every 18-degree increase.

Plant species vary in the amount of water they need to resist heat and maintain good health (hence their classification as low, medium, or high water use). New plant growth, tender seedlings, fruits and vegetables, and cool-season annuals are particularly susceptible to sun-related damage.

Plants exhibit different levels of heat damage, and it’s important to know the distinction. Wilting is the drooping or shriveling of plant tissues that occurs when they lack sufficient water; it’s reversible if plants are watered in time. (Large-leaved plants will usually wilt a little during peak daytime heat even with adequate water, but will recover when temperatures cool.) Heat stress is when plants begin to suffer irreversible heat-related damage; at this stage, some plants will try to conserve water by dropping leaves or buds. Sunburn (or “leaf scorch”) is when a plant’s leaves or non-woody parts are permanently and severely harmed by excessive heat or sunlight; leaves develop dried brown patches or margins and they eventually wither and fall off. Sunscald is the cracking, discoloration, and warping of bark that occurs when the trunk or branches of a woody plant get too much sun exposure; the damage is permanent and very harmful since it increases the plant’s disease susceptibility.

Follow these simple guidelines to minimize heat damage:

  • Conserve soil moisture and protect plant roots from excessive heat by covering bare ground with a 2- to 4-inch-thick layer of organic mulch—wood chips, shredded bark, leaves.
  • Don’t place inorganic mulches—sand, pebbles, rocks, shredded rubber—or black-tinted mulch near plants in sunny locations (with the exception of desert-adapted plants), because these materials collect and radiate heat.
  • Follow the principle of “right plant, right place.” Select plants adapted to our Mediterranean climate and choose planting locations with proper exposure. (No shade-loving plants in full sun!)
  • Don’t heavily prune trees and shrubs in summer, because this can suddenly expose tender bark to the sun’s intense rays. It also encourages a flush of heat-sensitive new growth and places additional energy and water demands upon heat-stressed plants.
  • Avoid planting during peak summer heat; this stresses plants and compromises their chances of successful establishment. Delay planting until fall, or (if you must plant this season) wait until a cooler spell, plant in the evening, and water deeply after planting.
  • Keep potted plants well watered and (if possible) move them to shadier locations. Use light-colored or plastic containers, which absorb and transmit less heat than dark-colored containers or those made of ceramic, cement, or metal. Hydrogels (water-retaining polymer granules) can be mixed into potting soil to help hold moisture.
  • Whitewash trunks of young trees to help prevent sunscald. Mix equal parts water and white interior latex paint, then apply it from 1 inch below ground to at least 2 feet above ground.
  • Use strategically placed shade cloth to shelter plants.
  • Ensure that plants receive appropriate and consistent levels of water, and check irrigation systems for proper operation. Do this yourself, or enlist the services of a Qualified Water Efficient Landscaper (

Just in case you’re wondering, it’s a myth that water droplets act as miniature magnifying glasses and burn leaves. Overhead watering generally should be avoided for water conservation and disease prevention purposes. . . but sometimes wilting plants (like us!) appreciate a cool sprinkling on a hot summer day.

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

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    Lee Miller

    Lee Miller is a University of Delaware graduate and retired fisheries biologist, he gardens on 10 acres and makes wine each year with the help of a cadre of friends. However, his first love is gardening and he grows various fruit trees, heirloom ... Read Full

    Marcy Sousa

    Marcy Sousa is the San Joaquin County UC Master Gardener Program Coordinator. She is a Stockton native and enjoys teaching others about gardening. She has her bachelors from Stanislaus State in Permaculture. She has been with the program since 2007. Read Full

    Nadia Zane

    Nadia Zane is a UC Master Gardener, a landscape designer and Stockton native. She has a fondness for California native plants and sustainable landscaping, which she utilizes in her work for Native Beauty Garden Design. She is a member of the CA ... Read Full
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