Fundamental facts about fertilizers

Spring is almost upon us, and with the season comes a rush of new plant growth and the urge to spend time in our gardens. Although fertilizer might seem a dry topic, give it some thought before you visit your favorite nursery.

Fertilizing plants is often equated with “feeding” them, but plants produce their own food through photosynthesis, using the sun’s energy to convert carbon dioxide and water to sugars and oxygen. Fertilizers do, however, provide plants with essential nutrients for cell development, function, and growth.

The basic purpose of fertilizers is to replace soil nutrients that deplete over time. Soil composition and pH have a direct effect on what nutrients can be absorbed by plants and how efficiently, so it’s wise to do a basic soil test before choosing or using a fertilizer to remedy any apparent nutrient deficiencies.

Fertilizers come in two basic types: organic (those derived from natural sources, including plant compost, animal manure, fish emulsion, and bone meal) and inorganic (composed of synthetic chemicals). Organic fertilizers have many benefits: they release nutrients over a long period; they improve the structure and water-holding capacity of soil; and they have a complex profile of macro- and micronutrients. The downside is that they’re more expensive and can vary in content or quality. Inorganic fertilizers release nutrients quickly, are consistent in composition, and are less expensive, but they don’t improve soil quality or contain as many nutrients.

Fertilizer bag with N-P-K ratio, showing each nutrient in its usual chemical form

Every fertilizer label shows something called the “N-P-K” ratio, which indicates the percentage by volume of nitrogen (N), phosphorus (P), and potassium (K). A “balanced” fertilizer has equal amounts of each of these three plant macronutrients; for example, a product labeled 16-16-16 has 16% N, 16% P, 16% K, and 52% other ingredients. A “complete” fertilizer contains all three major nutrients; an “incomplete” fertilizer has only one or two of them.

You might think, “If I use more fertilizer than recommended, my plants will grow even better.” No! Many serious problems can result from overuse of fertilizers. Too much fertilizer can burn plant roots and foliage; surplus nitrogen can leach into and pollute water; and excess nutrients can over-stimulate plant growth, leading to an unnecessary cycle of frequent pruning and stressed, disease-susceptible plants. Fertilizers should always be applied according to the instructions.

It’s also tempting to try shortcuts, and rationalize, “One kind of fertilizer will be fine for all my plants.” Wrong! Plants have unique nutrient requirements, and different fertilizers are formulated for different purposes. For example, many plants native to Australia can be harmed or killed by phosphorus-containing fertilizers, while other plants need phosphorus to thrive. A fertilizer intended for citrus trees is different from that designed for acid-loving azaleas and camellias… and so on.

Timing is another key consideration: season, rainfall, planting dates, and other factors are important in determining the right time to fertilize. If deciding when to fertilize shrubs and trees, their age, maturity, and species should be considered. Lawns are still another matter, and homeowners tend to apply fertilizer on lawns unnecessarily and wastefully.

An effective alternative to commercial lawn fertilizers is the easy practice of “grasscycling.” Grass clippings become natural fertilizer when they’re allowed to remain in place after mowing – they decompose and return nutrients to the soil. Grasscycling is often thought of as a relatively new sustainable practice, but its benefits have been known for many decades. I recently stumbled across a 1924 article from a Midwestern newspaper that cited this advice from the U.S. Department of Agriculture: “Cuttings should begin early with the lawn mower set as high as possible and should be repeated frequently. The clippings should all remain upon the lawn. The more of these clippings that can be retained about the roots of the grass the better the chances for a good lawn.” Nowadays, lawnmowers can be fitted with special mulching blades to make the process more efficient and the clipping size small.

By now, it should be clear that fertilizing is a very complex topic with far more detail than can be covered here. Before you fertilize, make sure that you—or those you hire to care for your garden—fully understand the specific goal of fertilizing; the product that will best meet that goal; and the proper rate, method, and timing for applying the chosen fertilizer.

Two excellent online resources are “A Gardener’s Guide to Fertilizing Trees and Shrubs” (NC State University) and “The UC Guide to Healthy Lawns” (UC IPM). You can also consult the California Master Gardener Handbook (Chapter 3 – Soil and Fertilizer Management) for in-depth guidance.

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


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Getting the dirt on earthworms

Earthworms. They’re so small and seemingly insignificant that we hardly give them a second thought.

These squirmy denizens of the dirt usually go about their lives unseen—they’re revealed to us only when upturned in a shovelful of soil or when stranded on pavement after a drenching rain. (Worms crawl out of the ground during heavy storms because they breathe air through their skin and can drown if the soil is saturated with water.)

Even though they can evoke a squeamish response, earthworms are good for the garden. They burrow and create long tunnels through the soil, which helps aerate and loosen it, creates channels for movement of water and oxygen, and allows plant roots to penetrate more easily. They help mix plant matter into the topsoil where beneficial microorganisms can decompose it. They consume organic matter such as fallen leaves, thereby recycling plant nutrients and increasing soil fertility. Worm castings (a.k.a. poop) are an excellent soil amendment since they’re rich in nutrients such as nitrogen, phosphorus, and potassium. Research even suggests that plants have improved disease resistance if planted in soil enriched with worm castings. Worms also provide a valuable source of food for birds, frogs, and other wildlife (not to mention being gobbled up by backyard chickens and fish on hooks).

Most of our native local species of worms have been destroyed or displaced by human activity; the kinds we usually see are descendants of hardier worms intentionally or accidentally introduced to North America by early European and Asian immigrants. There are now about 180 different species of earthworms in the U.S. and Canada, a third of which are non-native (including night crawlers). The typical garden earthworms are NOT the same as redworms or “red wigglers” (Eisenia foetida), the non-native species most commonly recommended for use in home worm composting.

Earthworms are primitive but fascinating creatures. They don’t have eyes, but they do have special light-detecting receptors. Light is a bad thing for creatures whose natural habitat is underground, and worms have evolved to move away from light sources, hence their burrowing instinct. They “hear” by detecting vibrations, and they produce mucus or “slime” in reaction to stress (e.g. being yanked from the ground). They also have voracious appetites: some species can eat their weight in organic matter every day.

Worms are hermaphroditic: each worm has both male and female reproductive organs in its elongated, muscular, tube-like body. Typically, two earthworms join side-by-side in opposing directions to mate, and each member of the pair produces an egg capsule from which one to several immature worms eventually emerge. Redworms are among the most prolific breeders.

In part due to its reproductive success, some Native American cultures revere the earthworm totem as a symbol of fertility, productive thought, and acceptance of emotions. In our modern society, the worm can represent either the beneficent (as in the sweet, bespectacled bookworm) or malicious (as in harmful software that lurks in the Internet).

A common earthworm with castings (Univ. of CA)













This is a good time to discredit a common misconception about worms. If a worm is cut in half by a shovel or by an over-enthusiastic tug from a curious child, the two parts won’t heal and live to create new worms. The head end (with its tiny brain and five hearts) can’t survive without the tail end (with its digestive system), and the worm simply dies.

You can use several techniques to encourage greater earthworm populations in your garden: (1) Avoid frequent tilling or cultivation of soil; (2) Minimize the use of synthetic fertilizers and pesticides, all of which disturb naturally occurring soil micro- and macro-organisms; (3) Allow leaf litter to remain on soil year-round, to provide a food source for worms; and (4) “Sheet mulch” bare soil, using layers of cardboard, mulch, and compost to keep soil cool and moist and to provide a source of organic material for worms to eat.

A word of caution: don’t dump unused live bait worms in a remote natural area. Many forest and mountain environments are naturally devoid of earthworms, and introducing them to those areas can be harmful. Forests often depend on a dense, protective, year-round layer of leaf litter, and earthworms will rapidly consume that thick organic mat.

For more about earthworms in our ecosystem, go online to and search for the article Earthworm Ecology in California, or read the book “The Earth Moved: On the Remarkable Achievements of Earthworms” by Amy Stewart.

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




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Worms Turn Food Waste Into Garden Gold

Worms make quick work of your kitchen scraps, leaving behind a nutritious amendment for your soil

One of the best ways to improve your soil and plant health is to apply compost, which is decomposed organic matter full of beneficial microbes. However, managing a pile takes time, space, a strong back, and the right kinds of organic materials to achieve the characterstics of quality compost. For those of you living on tiny urban lots with busy schedules or limited physical abilities, you can still turn food waste into an excellent soil amendment by harnessing the power of worms.

Yes, you read that correctly: worms.

I don’t mean tossing food on the ground for worms and less desirable wildlife find. I am talking about vermicomposting, the process in which worms eat your kitchen scraps so the bacteria in their guts can break down nutrients into a form that plants can use. It is a tidy, contained system that recylces food waste, feeds the soil, and connects us with the circle of life (sans heart-wrenching deaths of cartoon lions).

This amazing process requires a bin and a few other ingredients. People have used many different types of containers, and size depends upon how much food waste you produce. However wide the bin is, it should be no deeper than 12 inches. A bin measuring 2′ wide and 4′ long is good for a family of four. Make sure to drill holes 3/8” to 1/4” wide in the sides, top, and bottom. Elevate off the ground on blocks and place a drainage tray underneath to catch any drips (only overly-wet bins will have a lot of drippings).

Next you need to get bedding. Bedding provides worms with a place to get away from kitchen scraps to reproduce; it also provides a food source if kitchen scraps are scarce (or unfavorable). The simplest source of bedding is shredded newspaper, but you can also use regular paper, corrugated cardboard, dried leaves (watch for chemicals), or coconut coir. Bedding material needs to be damp enough to feel like a wrung-out sponge. Add a handful of soil, which contains grit for their digestion.

Worms eat almost anything that was once living, but if this is your first time, it’s best to stick with vegetable and fruit scraps for the first month or so until you can guage how much they will eat. Minimize pungent foods such as citrus and onions; speed up the process by chopping food into little pieces. Worms eat their weight in food every 5-7 days, but observe them carefully. As populations grow and bedding disappears (i.e. gets eaten), you can add more food. Be sure to bury food at least 1” deep to keep fruit flies away. Never feed them pet feces, non-biodegradable materials, or scraps with a high salt or fat content (worms will eventually eat salty/fatty items, but don’t put in a lot all at once).

There are thousands of worm species worldwide, but only a few are good candidates for worm bins. Redworms (Eisenia fetida) are the the most common, as they live in groups, feed on organic matter at the soil surface (this is why your bin should be less than 12” deep), and lack feelings of wanderlust, making them ideal for closed quarters. Start with a pound of worms, which can be purchased at fishing supply stores or online. Be sure to cover the bin to block out light.

Worms turn their bedding and kitchen scraps into a fine, dark material similar to ground coffee. The simplest harvesting method involves shoving the finished material to one side of the bin, placing fresh bedding and food in the empty side, and waiting for the worms to migrate. This could take several weeks and will never be a complete evacuation. Dumping the bin out onto a large, plastic sheet and scooping the vermicompost off the top (allow worms to work their way down by shining a lamp on the pile) is more thorough and allows you to evaluate whether you want to make any changes in your worm routine.

Although vermicompost is great for any garden plant, it is especially beneficial for veggies. Apartment-dwellers can practice vermicomposting as well and use the finished product on potted plants or give it to friends with gardens. It’s difficult to use too much; try to go with a minimum 1/4″ layer. You can scratch it lightly into the soil if desired, especially if you do not use mulch, which prevents it from forming a crusty layer in hot, dry weather.

For more tips and tricks, see Mary Appelhof’s excellent book on vermicomposting, entitled Worms Eat My Garbage (Flowerfield Enterprises, 1997).

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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Why Soil is Better Than Dirt


This compost bin is a great place to recycle garden clippings and kitchen scraps into food for the soil.

We’ve all heard the words “soil” and “dirt,” but what’s the difference? Both have the same basic components: particles of sand, silt, clay, and organic matter. The difference lies in how they function: dirt is where we stick our plants and dump water, fertilizers, and pesticides in the hopes of keeping plants alive; it loiters beneath our feet, supporting the weight of everything from humans to skyscrapers, all the while being completely ignored by the average citizen.

Soil, on the other hand, deserves a lot more respect. It contains a thriving community of organisms, many of which interact directly with plant roots to the benefit of all. This mutually beneficial relationship is crucial to plant health and can make gardening easier on humans if we allow the process to go along undisturbed.

One of the most important services soil organisms provide is making nutrients available to plants. The area immediately surrounding plant roots is covered with bacteria and fungi, which eat 50% of the sugars produced during plant photosynthesis. They also feed on nutrients from the surrounding soil, whose crystalline structure makes them unusable to plants. Bacteria and fungi have the enzymes and acids to break down these nutrients into forms plants can use, which is released when microscopic predators such as nematodes and protozoa come along and burst them open for a snack.

The living layer around plant roots, called a biofilm, also provides protection. A strong population of beneficial organisms crowds out invading pathogens and keeps existing bad guys in check. This biofilm is slightly alkaline, ensuring that the nutrients released by the bacteria and fungi will not be tied up by an overly acidic or alkaline environment. Remember that just because your soil may test as being extremely alkaline (rarely acidic in California), plants and organisms work as a team to change their lot in life.

The powers of living soil don’t end here; outside of the biofilm, organisms eat dead plant matter, releasing nutrients back into the soil. They secrete fluids (my apologies to squeamish readers) that bind together soil into little clumps called aggregates, which create air channels. These channels provide drainage and oxygen flow, the latter of which is essential in preventing anaerobic organisms and their toxic wastes from flourishing.

How do you know if your garden is full of dirt or soil? Think about how you treat your soil: dirt results from the over use of synthetic fertilizers, pesticides, inorganic amendments, and frequent tillage, leaving you with a heavier work load to make up for the lack or organisms. Another dirt-indicator is dead plant matter (“detritus”) that sits on the bare ground for months without decaying at all. Real soil contains the life to start decomposition quickly; in fact, keeping soil bare is a sure way to remove nutrients and starve soil organisms, leaving you with dirt.

Obtaining soil is not overly complex: apply good compost, which is organic matter that has been fully decomposed by bacteria and fungi. This acts as an inoculant to repopulate your soil with the organisms to build a healhty food web. Depending on your situation (and physical ability), compost may be difficult to make; compost can be purchased, but quality material is expensive, so apply where it is most needed, such as around vegetables or prized ornamentals.

Compost-making requires another article (and a certain amount of work), but the reduction in chemical use and increase in plant health is worth it. Help your soil organisms along by looking into composting at <>. If nothing else, switch to organic fertilizers and leave non-diseased detritus (or organic mulch such as bark)  on the soil surface to feed soil organisms and recycle nutrients whenever possible.

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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Time for seed searching.

A newspaper mulch for onions keeps winter weeds at bay. Lee Miller photo

These past few days the plant and seed catalogues are starting to arrive to remind us that spring is just around the corner. With all the rain lately it is not timely to be in the garden. Walking on wet soil can cause soil compaction, so it is a good time to stay inside. That said, I did have the foresight or perhaps good luck to spread wood chips in the walkway between Dahlia rows before the rains were heavy. Hence, I was able to get out between storms and dig Dahlia tubers because the wood chips kept mud at bay. I am also glad I planted my garlic and onions through repurposed Records which keeps down the weeds during the winter. It is difficult to be weeding in this weather and the weeds are thriving with the rain.

It is best to enjoy the rain while perusing some catalogues by the fireside. You can think about new vegetables and old vegetables to try out this coming season. I like to grow tasty heirloom tomatoes and I am always willing to try a few new varieties. One of the catalogues I received recently was from Tomato Growers Supply Co. They offer seeds for about 600 varieties of tomatoes and a few hundred peppers which should be enough to keep trying new tomatoes and pepper varieties for years. They have an on-line catalogue as well at:  I have bought seeds from them in the past and have been satisfied with their seeds.

Of course you can save your own seeds from open-pollenated varieties. These are not hybrid seeds. Saved hybrid seeds will not produce a plant like the parent F1 generation hybrid, but will likely revert to one of the parents. Hybrids do often offer the advantage of inbred genetic resistant to diseases and can be tasty as well.

Of course there are lots of seed purveyors around and if you want to check out how reliable they are, you can go to Dave’s Garden website ( ) and check out the number of negative or positive reviews on nurseries and seed houses in their Garden Watchdog page. One seed company that I have used for research, because it carries lots of peppers and tomatoes, had 83 negative comments, 14 neutral and 32 positive ones. That is a pretty sorry record. Thus it is good to check out seed houses and not get burned.

Seeds for tomatoes, peppers and eggplants as well as many flowers need to be started in late January or early February to get them sized right for April planting. If seeds have poor germination, a common complaint, then it throws off the timing of planting, or may result in a desired cultivar not getting planted this season.

We are fortunate here in Stockton to have our very own seed house, Lockhart seeds, and they carry a fair range of bulbs and seeds for vegetables and flowers. It is fun to go into their store, because it is a heirloom of a seed store with old varnished oak seed cabinets, 3 inch tongue and groove wood floors and a unique old-fashioned, cozy charm. Such stores were a fixture in many cities years ago, but many have disappeared.  Our big box stores also carry a variety of seeds.

One seed purveyor I like to support is the Seed-Saver’s Exchange which is a non-profit organization that has a seed bank for heirloom seeds that have come from various sources including Native Americans and the offspring of immigrant families that brought seeds of their  favorite vegetables when they emigrated to America.  It was started in 1975 by Diane Ott Whealy and her husband, who wanted to save her grandfather’s ‘German Pink’ tomato and a morning glory for future generations.

From that modest start of saving two heirlooms, the SSE has grown into a large enterprise with thousands of seeds in their seed bank. Today they have 13,000 supporting members and have 20,000 plant varieties that they maintain on a 890 acre, Heritage Farm near Decorah, Iowa. They offer some of their best heirlooms in a beautiful, well-illustrated catalogue and their materials are also accessible on line at:

Another good heirloom seed company is Baker Creek Heirloom Seed Co. which was started in 1998 and has along with SSE promoted interest in maintaining and providing heirloom seeds.  It is based in Missouri, but also has a seed store in an old bank in downtown Petaluma; it has a website catalogue as well: .  Dave’s Garden Watchdog lists 1029 positive to 40 negatives for this company. That is a pretty good endorsement. Where ever you find your seeds or plants for this year’s garden, may you find joy and happiness in gardening in 2017.

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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Is a greenhouse in your gardening future?

My greenhouse constructed mostly of salvaged materials.

It will soon be time to start seeds in my greenhouse. I built the greenhouse from material that I scrounged over several years and finally got around to putting it all together about 10 years ago. I have enjoyed my greenhouse so much that I wish that I had built it much sooner. There is something indescribably relaxing to be with seeds and plants in a cozy, warm, greenhouse when the outside weather is foul.

There are several things to consider when planning and installing a green house. Is there a site on your property that will provide the solar inputs needed for the green house to work?  Shading by trees or other buildings is generally undesired and orientation is important. The long axis of the green house should face south and it can be as much as 20 degrees off true south toward the west to optimize solar exposure.

True south is where the sun is at noon so you can use that as a guide or a magnetic compass, but you will need to adjust the compass reading for true north by the declination value for the area. I prefer the sun at noon which is simple to do this time of year. This is also the best time of year to see if there are shade obstructions to your site as the sun is low in the sky and winter and early spring is the time when a greenhouse is most useful.

To what purposes will you use your green house is another consideration. If you only plan to over winter frost-sensitive plants then perhaps you don’t need electricity.  However, if you are going to actually use it for starting plants from seeds or cuttings then water and electricity are very important and you will need to consider this in locating the greenhouse. It is also important to have good drainage and, if possible, shelter from wind which can diminish interior heat. My greenhouse is on the south side of a shop building and therefore electricity was easy to access and the building blocks north winds. It is also good to have a wide path to the green house for moving plants, compost, potting materials, etc. to and from the structure with a garden cart or wheel barrow.

I built my shed green house of glass panels. My neighbor had worked at a glass shop and had saved some 2 ft x 6 ft. glass panels for years and generously gave them to me for the roof to get them out of his garage. I also had saved some patio glass doors that I relieved someone of at the dump 25 plus years ago. I used these for the south facing wall. The back of the green house was covered with redwood boards I salvaged from the old tank house that blew over in a 1978 December storm. The frame I made from new 4×4 redwood posts and 2×4’s.

Out-fitting the green house, once built, is the next job. A bench space makes it is easier to work with plants and it runs the length of the greenhouse. It was decked with salvaged redwood fence boards. If you are starting plants from seed—lettuce, tomatoes, peppers, eggplant or flowers—in January or February you will need some heat supplied by heating mats and you will need auxiliary lighting on a timer. Day length is too short for plants at this time of year so I provide about 14 hours of fluorescent lighting to the plants once they have germinated.  Otherwise you will end up with leggy, spindly plants that are reaching for more light. I achieve this using a

Grow rack with lights and heating mats for starting seeds

grow rack with shelves for the heat mats and lights above them and a timer that controls all the lights. I had this setup in a garage, but after I built the greenhouse, I moved the grow rack into my greenhouse. After the plants are growing and day length increases, I transplant them to pots and move them to the bench.

There can be too much heat in a greenhouse. Hence a fan on a thermostat is good at controlling temperatures and a shade cloth may help reduce solar inputs in late winter when the sun is ascendant. Solar powered vents can also reduce temperatures on small greenhouses.

You can buy very nice greenhouses to meet your needs. You can buy them in kit form to be assembled. One very helpful website for planning and building your own greenhouse is: ( It is a matter of your capabilities, budget and what your needs are, but if you are an avid gardener, you will love having a greenhouse.

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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Please no crepe murders

Crepe myrtles are best left natural or pruned correctly

Winter is almost here and time to dormant prune ornamentals, roses and fruit trees. I am disturbed to see how some people despoil crepe myrtles (Lagerstroemia indica) when they prune them. The pruning technique used is called pollarding and it is defined as a tree cut back nearly to the trunk, so as to produce a dense mass of branches. Perhaps Wikipedia says it best about pollarding crepe myrtles “This is not a practice to use if one wants an attractive, healthy natural tree as the natural growth is stunted. Many times this is done in southern states of the USA to crepe myrtles, and is called “crepe murder” by some.” I can testify that I have seen crepe murder in our county.


Actually, crepe myrtles are better left unpruned than murdered. They will produce fewer blooms as there is less new growth which encourages blooms, but they are much more attractive with the natural look. Part of the charm of crepe myrtles is the bark, so leaving lots of the tree structure to display its colorful, peeling bark is so much better than pollarding it. Leaves are a gorgeous crimson each fall providing another esthetic feature.

Because crepe myrtles bloom on new wood, pruning does encourage new growth and that is why they are often pollarded to provide new growth. However, there are more esthetic and healthier ways to assure this. I came up with my own method years ago and two years ago while visiting the UC Davis campus, I saw that others too had used the same approach to pruning crepe myrtles.

Crepe myrtle pruned as an open vase

I train crepe myrtles like a fruit tree with an open center as seen in the photograph. This openness allows sunlight and air into the center, reducing diseases such as powdery mildew and promotes new growth for blooms. A heading cut on a young tree at about 3 to 4 feet will create branches to be trained to an open vase. There is a tendency for the crepe myrtle to have multiple trunks, but I prefer to select one main trunk and work with it. However, you can create an open vase tree with multiple trunks from the ground, especially if you start to work with a tree established in this manner: see  Select no more than 3 to 5 well-spaced trunks and prune out the rest. Crepe myrtles often send up suckers near the base which should also be removed.

After selecting a single trunk, it is a matter of making choices of which of the new shoots will be selected to create the vase shape of the tree. Select no more than 3-5 main scaffold branches. I usually head these at 2-4 feet or so to encourage branching. These branches in turn can be headed at 2-3 feet the following year to produce secondary scaffolds. At some point when the tree is shaped and at a sufficient height, I truncate the new shoots to a two bud spur. The choice is often for spurs which will keep the tree opening up. Pay attention always to which way the buds are facing on your two-bud spur selection as well as scaffold selections. Buds are usually located opposite each other in alternating sets, i.e., the next set is 90 degrees from first, so in some cases leaving 4 buds will provide the best directions for the shoots because the top buds will usually dominate. Last year’s two-bud spur may produce two or three shoots, so you will need to reduce this to one to select the next two-bud spur.

You can keep the tree at whatever height you want. By selecting two bud spurs on each branch each year, you will only add about a foot to the tree in 6-8 years. If you want to shorten the tree you can cut back into old wood and the tree will push some vestigial buds and continue to bloom. Thus this method allows you to keep the tree at a reasonable height. I need a ladder to prune my trees, but you could keep the tree shorter if desired and staying off ladders is always safer.

Prune weak side growth to strengthen it and induce more vigor. This will help provide blooms in places other than at the top. More evenly distributed blooms are more appealing. Crepe myrtles come in a range of sizes and colors to suit your landscape needs. They do well in California and are drought tolerant as well as beautiful. Cheers to better pruning and enjoyment of crepe myrtles.

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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Garden fungi: harmful or beneficial?

With the arrival of drenching fall rainstorms, soils are replenished with moisture and mushrooms pop up with abandon, seemingly overnight. “Are they bad?” you ask. The answer: it depends.

There are more than 100,000 species of fungi worldwide. Approximately 10 percent of them cause plant diseases, while only one-tenth of a percent are harmful to animals. The vast majority of fungi are beneficial to the environment: they help decompose decaying plant matter into rich humus and nutrients, break down toxic chemicals into non-toxic ones, or act in ways that encourage plant growth.

The terms “fungi” and “mushroom” are often used interchangeably, but they’re not the same thing. Think of a fungus as a living iceberg with only the upper tip visible. The above ground protrusion we know as a mushroom is simply the visible reproductive “fruit” of the main, seldom-seen fungal structure called the mycelium, which is a tangled mass of microscopic, threadlike filaments called hyphae. The mycelium grows where the fungus’s food source is located: in the soil, in rotting wood or plant matter, or in a host plant. A mature mycelium produces fruiting bodies called sporangia, and a mushroom is simply a very large sporangium. Each sporangium contains vast numbers of miniscule spores (the fungal equivalent of seeds). Once the spores ripen they disperse, germinate, and sprout new hyphae. Most fungi require warm, moist conditions to grow.

Lawn fungus mushrooms (Photo by Jack Kelly Clark, UC IPM)











Most common garden mushrooms—“toadstool” types or puffballs—grow on or near the ground and are beneficial decomposing fungi. The same applies to the shelf-like mushrooms that grow on dead trees or wood. However, if fungal mats or mushrooms sprout from a living tree, this indicates a potentially severe problem, since rot is already present. The more insidious fungus Armillaria mellea actually attacks many trees and shrubs and produces clusters of golden brown mushrooms.

Puffball fungus with black spores (Photo by R. Michael Davis, UC IPM)











If you prefer to remove mushrooms from your lawn or garden because they’re unattractive or because they might be eaten by young children or pets, simply hand pick and dispose of them as they emerge. NEVER eat wild mushrooms unless you’re an expert in their identification. Some mushrooms are harmless, but many are poisonous and can cause symptoms ranging from temporary vomiting to permanent and fatal organ damage.

The beneficial mycorrhizal fungi deserve special attention. These fungi form symbiotic associations with the roots of many plant species; the word mycorrhiza literally means “root fungus” in Greek. Once these fungi colonize plant roots they spread their fine hyphae out into the soil, helping plants absorb water and nutrients far more efficiently than they could on their own. In exchange, plants “feed” the fungi with sugar compounds. Some plants are highly dependent on this partnership—especially oaks, conifers, and many native shrubs—and 90 to 95 percent of plant species are believed to benefit from fungal symbiosis.

Mycorrhizal fungi play an important role in helping plants survive drought conditions, but they can survive only in association with living plants, not in bare soil. To encourage a healthy population of these fungi, keep soil planted year-round, minimize soil-disturbing activities like rototilling, and avoid the use of pesticides and chemical fertilizers.

Some fungus species are pathogenic, and cause harmful plant and turf diseases such as anthracnose, powdery mildew, rust, root rot, leaf spot, and blights. Landscape conditions such as poor air circulation, excessive moisture, improper watering, and over-fertilizing encourage many of these fungal diseases. Proper cultural care practices are usually very effective in controlling the responsible fungi without the use of chemicals.

Most fungicides are preventive (not curative) and can only protect uninfected plant tissue; they must be used before infection occurs or when symptoms first appear. If it becomes necessary to use a fungicide treatment, research the affected plant and type of fungus carefully, choose the proper product, and apply it according to label instructions to avoid causing harm to yourself and the environment. Remember that pesticide labels are legally binding documents; it’s both dangerous and illegal to apply or dispose of pesticides in a manner inconsistent with the instructions.

For more information on fungi see the UC IPM Pest Note entitled, “Mushrooms and Other Nuisance Fungi in Lawns.”

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




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The magic of persimmons

A persimmon tree in fall is a splendid sight. Its leaves turn vibrant shades of yellow, orange, and red, and once they drop the decorative, bright orange fruits remain hanging from the bare branches like well-placed ornaments.

The two most common persimmon varieties, and one lesser-known one, are:

Fuyu: The medium-sized, flattened fruits of this variety are shaped like a common tomato, and they ripen to an orange or orange-red color. Their flesh is orange, firm, crunchy, and sweet when ripe, and they are best eaten raw like apples.

Hachiya:The large fruits of this variety have pointed ends and are shaped like plump acorns; they are deep orange-red when ripe. If you mistakenly bite into one before it’s fully ripe, you won’t repeat the mistake, since the flesh of this variety is highly astringent when firm and it will leave your mouth unpleasantly dry. Once allowed to become soft-ripe, the flesh becomes very sweet, without astringency. It can then be scooped from the skin with a spoon, to be eaten fresh or used in baking.

Chocolate: The ripe fruits of this variety are shaped and colored like those of Hachiya. Interestingly, the inner flesh is astringent and light-colored if the fruit is left un-pollinated and seedless, but the flesh turns sweet, slightly spicy/chocolaty, and brown when pollinated and seedy.

Fuyu persimmons (Photo courtesy of Sonoma County Master Gardeners)

Hachiya persimmon (Photo courtesy of Sonoma County Master Gardeners)


Harvesting and storing

Persimmons begin to ripen in September and are ready to harvest in November. Harvest Fuyus when fully colored and firm. Hachiya persimmons can be allowed to get soft-ripe while still on the tree, but it’s easier to harvest them when brightly colored but still firm. They will finish ripening indoors.

Cut the stems about 1 inch above the fruit, leaving the four-lobed green calyx at the top. Don’t pull the fruits off the tree since this can damage them or break the brittle branches.

Once harvested, keep the crisp-ripe Fuyu persimmons away from fruits that emit ethylene gas (apples, bananas) or they will lose their firm texture. The opposite is true for Hachiya persimmons intended for use in baking or for eating raw; ethylene gas will hasten their ripening to a soft and non-astringent state.

Persimmons can be stored for up to a month in the refrigerator; remove them to allow the ripening process to finish, if necessary.

Preserving persimmons

If you’d like to enjoy persimmons throughout the year, you can preserve them using a couple different methods:

Dehydrated slices: Begin with firm-ripe and fully-colored Hachiya or Fuyu persimmons; interestingly, the dehydration process removes the astringent quality of the firm Hachiya persimmons while preserving and concentrating the sweetness. The skin may be left on the fruit, but blemishes and bruises should be cut away. Slice the persimmons across the core into evenly thick slabs ¼ to ⅓ inch thick. Arrange slices on the dehydrator trays and dry at 120° for 7 to 10 hours until they are leathery but still flexible. The vibrant color of the persimmon fruit is preserved, and the sweetness is enhanced. Store slices in airtight bags or containers in the refrigerator.

Hoshigaki: This is the traditional Japanese version of dried persimmons. The drying process is long and the end results are decidedly unattractive, but the flavor is delicious. To prepare hoshigaki, start with persimmons that have ripened to a bright orange color but that are firm (not soft-ripe) and un-bruised. Hachiyas work best, but Fuyus can also be used. Wash the persimmons and break off the calyx “leaves,” but retain the stem. Peel off the rind, then tie string securely to the stem. Hang the persimmons in a dry location (indoors or outdoors) that gets direct sunlight and good air circulation but is protected from rain and animals. Protect the surface underneath to protect from accidental falls and messy “splats.” Every 3 to 4 days, gently massage the hang-drying fruits to break up the internal structure, being careful not to split or tear the outer layer. Don’t worry if a white powder develops on the outside; this is sugar emerging to the surface. After 5 to 8 weeks, when the pulp has set, you’ll be rewarded with orange-brown, chewy relics having a sublimely sweet flavor.

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


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Water Water, oh if it were only everywhere

A 1000 gallon tank used to water spring greenhouse plantings

The rainy season is here and it is a good time to think about conserving and saving whatever befalls us this season. NOAA’s Climate Prediction Center gives a 70 percent chance of La nina conditions to develop this fall and a 55 percent chance that it will persist through the winter. La nina conditions are characterized by cooler than average temperatures in the Central Pacific with a resulting cool and moist jet stream in the northern states and a drier jet stream in the southern tier of states. Hence dry conditions in Southern California and perhaps snow and rain north of San Francisco. Of course long range forecasting is an iffy proposition, but is seems unlikely that our county will have a wet winter.

So, what can we do to help with the drought which is likely to continue? We are already over drafting aquifers, so conserving water remains an essential activity and of course water is becoming more expensive which also encourages conservation. One approach is to plant drought tolerant plants and also to group plants by their water needs so that the irrigation can be hydro-zoned for efficient water use based on the plant’s water requirements.

Recently at the UC Master Gardener’s Demo garden open house, I helped retro-fit a sprinkler system with a drip irrigation setup for one of the gardens. We plugged all the sprinkler heads except for two. There two were installed with filters and we attached ½ inch drip lines with built in emitters at 18 inch spacing. This will save a lot of water as it puts the water right at the plant. Less water, fewer weeds are the benefits.  We used Netafim drip materials and for more information on using drip for landscapes you can find it here:

To keep water on your property where it does the most good rather than running down storm drains there are several things that you can do. Redirect water from driveways, walkways and hardscapes. This can be done by putting plastic or metal extensions and splashblocks on the downspout. This should also be done to keep water away from the house and foundation; see:

If hardscape have been constructed of porous concrete or porous asphalt materials this will allow water to drain through them. This is something to keep in mind if you replace any of these hardscapes in the future; see: Water kept on your property can replenish underground storage essential to landscape plants.

Water harvesting has been done in many areas of the world for 4000 years. Bermuda which consists of seven small islands was settled in 1609 and has very little potable water from aquifers. Hence the settlers there harvested rainwater from roofs and catchment areas into tanks or underground cisterns which was necessary to provide for household needs.  The farm house where I grew up had a cistern to collect rainwater from the roof and it was built in the 1880’s, before electric pumps were available to pump water. We are not in such dire straits yet, but we can harvest water from roofs to increase water available for garden and landscape use. Rain water that is harvested does not contain chlorine and is soft water, i.e., not containing calcium carbonate, iron or other compounds that make for hard water. Thus it is good water for plants.

There are many sources for barrels and tanks for water harvesting and it is possible to use a connected series of 50 gallon drums to harvest water from rooftops for gardens. Just do a google search on ‘rain barrels’ and you will see lots of choices. I was fortunate to purchase from a bulk water business, three 1000 gallon tanks for water harvesting. They were tanks with flaws that made them no longer fit for potable water, but work fine for collecting rainwater for garden uses. I use one for my entire spring greenhouse plant growing. The other two are used

Eight 50 gallon drums harvest rainwater for vegetable garden seed starts.

for landscape watering. I also have eight 50 gallon drums next to my garden shed which receive water from my garden shed roof. Though a small shed, in a good year I will have 400 gallons of water to use for hand watering of seedlings in my vegetable garden. For more information on water harvesting see:

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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    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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