Garden Coach's Blog for Gardeners

Giving Soil the Respect it Deserves

By: gardencoach, 8:11 PM GMT on February 25, 2013

“The soil is the great connector of lives, the source and destination of all. It is the healer and restorer and resurrector, by which disease passes into health, age into youth, death into life. Without proper care for it we can have no community, because without proper care for it we can have no life.”
-Wendell Berry

Soil is a largely overlooked and misunderstood part of the garden ecosystem, and as a result is often mistreated, or ignored, even abused. As with all dynamic ecosystems, there is interaction and interdependence in the garden. Much more is happening out of sight than we can ever know. This is particularly true of soil, which is about as out of sight as it’s possible to be. The importance of soil goes well beyond the fact that it supplies anchorage for plants and holds a reservoir of water on which roots can draw. It is a complex amalgam of mineral particles and organic matter developed over millennia and is inhabited by a universe of soil dwelling animals and billions of good and bad fungal and bacterial microorganisms that are essentially in an ongoing battle for balance. As hard as it may be to believe, a pinch of soil may contain as many as 100 billion bacteria, comparable to the number of stars in the galaxy.

Soil begins with the physical deterioration of bare rock, worn or broken off by the force of temperature, rain or wave action, and wind to form a loose aggregation. Chemical decomposition of the aggregates then occurs, beginning the process called weathering. When weathering reaches a point where a seed might germinate and take root, webs of relationships begin to develop between plant and the microscopic life underground. Several factors are at play in this process. The parent material, climate, topography, and types of organisms present evolve over time to create the multitude of soil types the world over, whether it’s the dense, humus rich soils of the great forests to the lean, dry and sandy soils of desert lands.

Soils can be residual, forming in place, or depositional, transported from elsewhere by gravity, or rivers or wind. They are named for their texture, which remains unchanged. Texture is the result of the combination of mineral particles, sand, silt, and clay that they contain. The ideal soil is loam, an optimum mixture of the three. It contains a healthy population of soil-dwelling organisms, has minerals, air pores for root growth, and excellent water retention. Since natural loam is elusive for most of us, we have to improve the soil structure, fortunately a quite achievable goal. Our soils are identified by the proportion of their mineral components, sand, silt, and clay. How these different types behave is fairly predictable. Clay soils, with greater surface area of their tiny particles, can easily become gooey and waterlogged, while the larger sand particles give water less to cling to and as a result dry out very quickly. Texture also determines how well soil holds onto nutrients and how quickly or slowly it will warm up in the spring.

Gardeners are often puzzled about what to do with their soil. As tempting as it is to believe the ubiquitous television advertisements that show a dejected man digging one bag of soil conditioner into poor, depleted soil only to joyously see a complete transformation take place immediately, we know this is not how things work.

When we discuss soil development, we’re talking about geologic time. Many of the old notions of soil improvement achieved by adding great quantities of organic material by deep digging, tilling, and otherwise disturbing the soil are falling out of favor. Let me say now that for edibles, these techniques are necessary and effective. Vegetable and fruit crops are heavy feeders and require additional organic material incorporated in the soil to take care of their intense nutritional needs during the growing season.

In gardens that support mostly ornamentals, the double-digging and tilling simply aren’t necessary, and the application of organic materials from the top down are becoming widely accepted as a benign and effective method of soil improvement. If you favor native plants, they are adapted to both climate and soil. Often, over-amended soil is detrimental to them. Believe it or not, you already have most of what is needed to improve your soil in your garden itself. You can gently loosen the soil by inserting and rocking a garden fork back and forth to allow better air circulation, but other than digging planting holes, there’s already an underground army at your disposal to make things better. All you have to do is supply the raw material.

Remember, an ecosystem works in cycles. Nothing is static. The leaves falling from your trees, the spent flowers from annuals or perennial plants, twigs, branches, these all are fodder for the compost that will nourish the life in the soil. To be sure, there are imbalances that may need to be addressed with specific fertilizers or amendments. Some plants require additional nutrients that compost alone may not provide. Knowing this comes with experience. But providing plants with healthy soil brimming with microorganisms is always at the heart of a thriving garden.

Remember, an ecosystem works in cycles. Nothing is static. The leaves falling from your trees, the spent flowers from annuals or perennial plants, twigs, branches, these all are fodder for the compost that will nourish the life in the soil. To be sure, there are imbalances that may need to be addressed with specific fertilizers or amendments. Some plants require additional nutrients that compost alone may not provide. Knowing this comes with experience. But providing plants with healthy soil brimming with microorganisms is always at the heart of a thriving garden.

Now, the natural processes that create this ideal situation are not nearly as attractive and effortless as that man working with his bag of magic soil improver. Just as above ground, there’s a food chain in the life of the soil. What we’re talking about is decomposition. In a continuous cycle of life and death, plants, flowers, and animals live and die. What remains is either eaten by a huge array of microorganisms living underground or carried there by animals like pill bugs, worms, or beetles, where it continues to break down further and further. Decomposers attract predators. Bacteria are eaten by protozoa, fungi trap and eat nematodes but are then eaten themselves. Larger animal like earthworms, large in the sense that you may be able to see them with the naked eye, not only transport decaying organic material but eat it themselves. You can begin to see that a balance is being achieved by soil biota with little assistance from us. Further, nutrients that are created from the decomposition processes are dissolved when water is added to the soil, providing roots with a constant supply of nourishment over time.

It’s when we deprive the ecosystem of the raw materials for decomposition that we run into problems. The desire for “clean” garden beds, raked clear of any and all organic materials, has an unintended negative consequence. Soil biota cannot survive without dead and decaying plants, which are the raw materials necessary for their work and will simply move away or die. Nutrient recycling will stop, and the garden will then have to be supported artificially by applications of fertilizers. Fertilizers derived from petrochemicals very effectively keep soil microorganisms from ever returning to your garden. The answer? Feed the soil, not the plants. This general rule will bring results that may surprise and achieve a peace you’ve never had with your soil.

Fortunately, there are many resources for learning how to make soil better. I’ll be the first to admit that there are some soils so difficult the only solution is to avoid planting in them. In these cases, using raised beds or building mounds may be the only alternative. Before giving up completely, though, give some remedial methods a try. To learn more about helping your ordinary garden soil be its best, here are some suggestions:

The Soil Food Web

The concept of the Soil Food Web was developed by Dr. Elaine Ingham. Her research and methodology has opened up a whole new way of looking at the soil, and I can’t recommend her methods strongly enough. She is a proponent of the benefits of compost and compost tea to improve normal soil and remediate problem soils. You can find out more about her at:

Soil Food Web about the work of Dr. Elaine Ingham

She and her surrogates offer classes throughout the country. She is now a director of the Rodale Institute.

Compost, Compost Tea and Worm Compost

The lynchpin of Dr. Ingham’s work is compost and actively aerated compost tea. You can learn to compost yourself by taking advantage of a wide variety of programs offered by community groups, organizations like Master Gardeners, and sanitary districts looking to reduce the green waste stream. Many municipalities now compost all green waste, including organic waste from restaurants, to create high-quality compost for the taking. Check with your local organizations to get details.

Mulching and Sheet Mulching

Mulching, the application of a thick layer of material over soil, is a very effective and effortless way of improving soil. Although it is often touted for weed suppression and conservation of water in the soil, using a physical barrier of organic material such as shredded bark, composted wood chips or clippings, composted sawdust, or even compost itself, contributes to soil health as it decomposes. It can be a long process, so be patient. In a season or two you’ll begin to see tremendous changes in the structure of your soil.

Sheet mulching, a method used in permaculture, utilizes cardboard or newspaper as the barrier against light reaching the soil surface. When covered with very thick layers of mulch (permaculturists often use straw), the soil is protected while microorganisms enrich and strengthen it. Check out more about this worldwide movement at:

sheet mulching and permaculture

Some Additional Information

If you wish to further your study and understanding of the importance of soil in our lives, there are several books and a movie I strongly recommend. Amy Stewart’s wonderful book about earthworms, The Earth Moved, (Algonquin Books of Chapel Hill, 2005) is highly readable and informative. Teaming With Microbes ,by Jeff Lowenfels and Wayne Lewis (Timber Press, 2006) is an introduction to the Soil Food Web.Dirt, The Ecstatic Skin of the Earth by William Bryant Logan, is a beautifully written homage to the wonders of soil. Dirt! The Movie , made in 2009, is an excellent and inspirational introduction to the concept of the life-giving properties of soil. It is easily purchased online and can be viewed online at several free sites.

Having healthy soil means having healthy plants and healthier humans. Living soil builds humus, holds onto water, filters pollutants, allows water and air to penetrate, and prevents runoff and sedimentation, the number one cause of polluted waterways. Every day we become more and more aware of the need to pay more attention to the humble material that makes it possible for us to sustain ourselves. Is your own community doing anything to raise awareness?

Gardening Pollution Drought

Updated: 6:15 PM GMT on March 08, 2013


What's in a Name?

By: gardencoach, 11:44 PM GMT on February 02, 2013

What’s in a Name?

Before you turn away, hear me out on the advantages of learning the basics of the scientific naming of plants. Latinized botanical names may be hard to spell, hard to remember, and in some cases, impossible to pronounce. In my experience, almost nothing strikes as much fear in the hearts of "dirt" gardeners like me as facing the botanical names of plants. During the years that I taught plant identification, it pained me to see the distress this prospect causes. It doesn’t have to be that way. It can be fun and quite rewarding. I’m far from expert, mostly self-taught, but I can assure you that learning botanical plant names increased my confidence and understanding in ways I appreciate every day.

There is a very good reason why scientific names are used. They are well organized, clear, and highly descriptive, full of hints about the plants they identify. Once you grasp the basics, you have the tools to help you understand the plant kingdom in a larger sense and, in a practical sense, the appropriate plants for your garden.

We’re moving inexorably toward spring, and if you’re not already thinking about what plants you’re going to buy, very soon you’re going to be itching to make a trip to the nursery or a plant sale. Knowing something about scientific naming will change the way you select and purchase plants. It will make it easier and more successful.

You should feel confident that, when you go to buy plants, you can read a nursery label or ask a nurseryperson for a particular plant. Another very important reason for learning how plants are named is that it will deepen and enrich your understanding of the very plants for which you develop particular affection or have success – usually those two go together. And to discover those plants have relatives with the same attributes? I guarantee that the first time you recognize plants’ botanical relationships to one another you will feel elated.

Why Botanical Names?

The major benefit of using botanical (Latinized) names for plants is consistency. Confusion arising from having many common names for the same plant is often cited as one of the main justifications for using botanical names. For example, the popular annual Impatiens has at least four common names, including touch-me-not, sultana, busy Lizzie, and patience plant. These common names are often regional, so in one part of the world the patience plant is well known but in other areas the name draws blank stares. Also, dependence on common names is misleading and can actually lead to gardening failures. What many call evening primroses are not primroses. True primroses, or Primula , have very different cultural needs from Oenothera, evening primroses. One prefers dampness and shade, the other flourishes in full sun and dryness. You can draw your own conclusions about how discouraging it would be to plant evening primroses in your woodland garden. Perhaps the best reason to use botanical names is that most of the many hundreds of thousands of named plants have no common name at all.

There is one and only one scientific name for a particular plant – think of common names of plants as nicknames and the scientific or botanical Latinized name as a formal name. These plant names are conferred and updated by the International Congress of Taxonomists, and they are based on the similarity of structure of the reproductive systems of plants.

Where did Botanical Names come from?

It was the Swedish botanist, naturalist, and physician Carl Linnaeus (1701-1778) who developed and formalized a system of classification of modern taxonomy. We refer to that system variously as scientific nomenclature, binomial nomenclature, or botanical Latin.

Linnaeus recognized the need for a naming convention that would organize and classify flowering plants. Early taxonomists of China (3000 BC) and Egypt (1500 BC) had worked at developing naming systems, but Linnaeus provided the key organizing principles that are still used today. The language he used is more accurately described as “Latinized” than pure Latin, and some of the descriptors have Greek roots as well.
Do you remember in grade school days learning about kingdom, phylum, class, order, family, genus, and species? This is what taxonomy is – the naming of biological organisms in a standardized hierarchical format from the general to the specific, from the greatest to the smallest identifiers.

For our purposes as gardeners, we want to talk about genus and species, the terminology you’ll use most frequently to identify plants. The species name is called, unappealingly in my view, the specific epithet, and includes the genus name followed by the species name. The specific epithet always appears in italics, with the first (genus) name capitalized and the second (species) name in lower case. One of the most important things to remember about these terms is that the species name describes the genus name. I’ll show you how in a minute.

I wondered which plant to use an example that would strike a familiar chord with most of you and decided to use the oak. In botanical Latin the genus name is Quercus. There are approximately 600 species of oak, and each one has that two-part name, genus and species. Let’s look at a few of the species to see how botanical Latin clarifies the plant in question. Quercus alba is the white oak, Quercus texana is the Texas oak, Quercus ilex the holly oak, Quercus virginiana the southern oak, and Quercus suber, the cork oak. You can readily see how obvious some of the descriptions are, but if you need help you can find a number of online botanical dictionaries or buy a book that defines unfamiliar words.

I have several reference books that I keep near my desk and refer to often. My two favorites are small and inexpensive, the Timber Press Dictionary of Plant Names by Allen J. Coombes and Algonquin Books Gardener's Latin by Bill Neal, each crammed with hundreds of entries. While two of the four oak names above are pretty self-evident, Quercus ilex may be somewhat more obscure until you discover that ilex is Latin for holly. Hmmm. So, the plant is named because its leaves resemble those of holly. Now you know that any time you see a botanical name with a species name ilex it will mean that the leaves of that plant look like holly.

What about the cork oak? Suber means cork or corky, and Quercus suber is native to the western Mediterranean. Its thick, corky bark is its glory and is also what makes it so valuable to humans. It is no surprise that the bark of these oaks is harvested to make corks for the fabulous wine that comes from grapes grown in Spain and France. One thing leads to another, and from this simple plant name you’ve learned something about a plant that plays a vital role in wine production in another part of the world.

The descriptors (specific epithets) refer to anything from color, size, smell, texture, or shape of leaves, bark or flowers, place of origin, even unusual characteristics like thorns or scales.

Variety and subspecies

Within particular species in the wild there exist plants that differ from the species but not sufficiently to create a separate species. These are referred to as varieties and are listed as “var.” in the scientific name. Similarly, when there are more significant differences from the species but still not enough to warrant a new species designation, the term subspecies is employed. In this instance, the plant is given its own Latinized and italicized name with the letters “ssp.” before the last part of the specific epithet. Unless you wish to pursue these naming conventions on your own, for our purposes you simply need to know what they mean when you see these terms in a book or on a label.


A hybrid is a plant that is a cross between two different species. Plants may hybridize naturally in the wild (some are much more prone to do this than others) or they may be deliberately hybridized by humans. A hybrid is always indicated by an “x” in the plant name, as illustrated below on a plant label for a boxwood.

Selection and Cultivar

Cultivar means cultivated variety, and we see more of these on the market as the years go by. The development of a cultivar happens in one of two ways. In nature, variations occur in plants. They may be markedly larger or smaller, flower color may be different, or leaves may differ in shape or color from the species. Sharp-eyed plants people spot these variations on their expeditions and take cuttings from the unusual plants they recognize as different and desirable. They return to the greenhouse, pot up those cuttings and observe that the difference is replicated in the new plants because the new plants are clones, identical to their parents.

In the nursery greenhouse setting, this breaking away from the species is also observed. Let’s say a grower sets out new plants of a particular species and when those plants bloom, all but one has white flowers. There is one plant that bears distinctive dark red flowers – a beautiful accident of nature. The grower will “select” out that new color and propagate it by cuttings, by cloning, to ensure that the characteristics are intact. Thus a new plant, a new cultivar, is created.

A grower may also select out food plants for a particular quality of fruit, disease resistance, or some other characteristic and deliberately clone them to create a new strain that originally occurred naturally. This technique has allowed some of the best varieties of plants to become widely available and has dramatically expanded the selections we make for our own gardens.
The cultivar has a different kind of name that you’ve no doubt seen before. Preceded by the genus and species name, the cultivar name is typically in English and is enclosed by single quotation marks, like ‘Supertunia Bordeaux’, below. It’s not unusual for the plant to be named in honor of a person, like Salvia clevelandii ‘Winnifred Gilman’ (named for a volunteer propagator at San Francisco Botanical Garden), or a special color, like Berberis thurnbergii ‘Limeglow’ (named for the brilliant lime green color of new leaves), but don’t be surprised to see a plant named after just about anything, including a cocktail, like Aquilegia skinnerii 'Tequila Sunrise'!

Note that the petunia cultivar below is also a hybird. It's a general rule that while hybrids can be bred into cultivars, because cultivars generally do not come true from seed they cannot be hybridized.

Family Matters

Once you become comfortable with scientific names, it’s inevitable that you’ll begin to notice the families that certain genera (plural for genus) belong to. Again, some will be familiar, like the Rosaceae, rose family, or the Asteraceae, aster family, but others will make you wonder, like the Fabiaceae (pea), Apiaceae (carrot, parsley), Lamiaceae (mint) and Poaceae (grass).

This sign from a botanical garden uses its standard naming protocol to provide the family name in the upper left corner, the Latinized botanical name in all capitals, and the common name in parentheses. Visiting botanical gardens is an excellent way to
practice recognizing plants by their botanical Latin names.

It’s helpful, for example, to know that the huge aster family, with 23,000 recognized species in more than 1,600 genera, contains plants that are easy to grow and highly attractive to wildlife. Think sunflower, zinnia, cosmos, coneflower, Shasta daisy, rudbeckia, the list goes on and on. Members of the aster family thrive almost all over the world.

I love the mint family because my favorite genus, Salvia, belongs to it. This family contains over 7,000 species in over 200 genera. There are over 900 species of Salvia in this family, something for every taste, every skill level, every season, and every garden. It also contains other easy plants like thyme, oregano, mint , germander, and lamb’s ears.

For someone else, it might be the rose family, which in addition to the perennial favorite rose bush includes cherry, plum, almond, strawberry, ash, hawthorn, and cotoneaster -- almost 3,000 species in 95 genera.

Well, there you have it. With a little practice and some patience, a world of knowledge that will enrich your gardening life is open to you. I would love to hear if you’ve decided to give botanical names a try.


About gardencoach

Susan Handjian is a garden educator in the San Francisco Bay Area. She was a contributing editor of Plants and Landscapes for Summer-Dry Climates.