How can we deal with all the bugs and diseases without using toxic poisons, and how can our gardens really produce without high-powered chemical fertilizers? Many people wanting to garden sustainably are asking these questions. And it is not easy to find the answers, partly because the answers are not simple. I want to admit this up front, but don’t be scared off, because it’s not that hard to garden sustainably once you get the hang of it. However you must know that you can’t just exchange a slam-bam chemical approach for a slam-bam sustainable approach.

          I started investigating this whole subject 35 years ago when I took over the management of a small apple orchard in Iowa. I attended a  Fruit Growers’ Assn. Conference held at the prestigious Iowa State University Agriculture School. It quickly became clear that the professors were acting as agents for the pesticide and chemical fertilizer companies whose salesmen filled the trade show. I was told there are two crops nobody can grow without lots of chemicals: apples and cotton. And they scoffed at an old-timer who told the group that he used geese to remove weeds instead of herbicides. The experience convinced me that I could not trust the university professors’ recommendations. That was when I took the organic road. Later I learned that most land grant universities were subsidized by chemical companies to test their products.

          So the first lesson for us on the subject of gardening without chemicals is: Don’t believe the people telling you that you can’t garden without chemicals, because most of them have something to gain by saying so. This was radical thinking in 1975. Now you may be wondering why make a point of something that is so obvious.

          This historical anecdote is valuable because it shows where we are coming from, and the forces that still influence us, though now they may be green-washed with clever names and slogans, using terms like “green” and “organic” when they have only added a few organic items to their chemical line. My point is: no matter what products or services are called, get the complete list of ingredients or products, especially if a professional is going to spray or apply something on your property. It may not be lethal to adults, but is it hazardous to infants, dogs, cats, bees, fish, frogs, beneficial insects or soil microorganisms?

          The truly sustainable products and companies will take the whole eco-system into consideration, and will talk more about supporting life that destroying life, more about balancing an eco-system rather than about killing an enemy, and more about teaching you a method than selling you a silver bullet.

          I admit, there is something very satisfying (to the ego) about spraying some bugs that are devouring our tomatoes and watching them drop dead at our feet, or sprinkling some granules on the lawn and seeing it bright green, thick and tall only a week later. Wow! Aren’t these crowd pleasers? The problem is, our instant gratification has been coming at a high price to our environment, because of the not-so-instant and often hidden consequences. Pesticides are designed to kill, but they don’t know when to stop killing. Quick-green-up chemical fertilizers that are not completely absorbed by the plants flow into our ground water, create dead zones in our seas, and change our atmosphere. On top of these effects is the tremendous pollution released in the manufacturing of these products.

          So what are the alternatives? I have been asking that question, researching the answers and testing them in my gardens and nursery for 35 years. Sustainability has recently reached a new level with new products and research surfacing every year, and it is hard to keep up with all the new developments. It is obvious, though, that we are now getting a clearer view of the organic path, and that we are far better equipped to garden organically than ever before. In addition, the word is out that organic gardening can not only give us a cleaner world and healthier food, but it can also significantly support the reduction of greenhouse gases.

          One of the most important themes of gardening organically and sustainably is: strong and healthy plants have few pests, and strong and healthy plants come from strong and healthy soil. As Wendell Berry, farmer and eloquent spokesman for sustainable agriculture, has explained: if a soil is deficient in a healthy soil life, the plants growing on that soil will also be deficient, and the animals and humans eating those plants will also be deficient. This is why I say that we cannot just switch from a chemical silver bullet to an organic silver bullet. A significant part of any sustainable solution is understanding the cyclical nature of nutrient sharing. We humans must do our share to give, not just take, from the nutrient cycle.

          The short answer to how to have a healthy soil life is to follow Naure’s example of returning organic matter to the soil every year, by mulching and adding composts and organic fertilizers. This process may take more time and care, like preparing a home-cooked meal from scratch, whereas using chemical fertilizers is like dining at the 7-11 on high fructose corn syrup, processed food and other imitation food stuffs. Chemical fertilizers are derived from petroleum. They are known to burn microorganisms and have been shown to require as much as ten times more water to prevent burning of plants. In addition their manufacture and use releases nitrous oxide, the most ozone-depleting substance made by man, and 300 times more potent as a greenhouse gas than carbon dioxide.

There are now many locally-produced sources of good organic soil amendments and fertilizers which are good for the plants, and responsible for far less greenhouse gas emissions.

Another important theme in organic/sustainable gardening is using plants that are well-adapted to our area. Sure, if you just love astilbe or rhododendrons, you can make a special area for them. But the majority of plants for the Front Range of Colorado should be water-thrifty and tolerant of alkaline soils, hot summers, cold winters, strong wind and rapidly changing conditions. They should also be resistant to our common pest and disease problems. Why plant a Jonathan apple, for example, that will be weakened by fireblight, require spraying and/or higher maintenance, when there are apple varieties resistant to fireblight. And we should focus on ornamentals, vegetables and fruits that flower or ripen in our shorter growing season. I would love to grow Maximillian Sunflower, but it doesn’t bloom until October and is often smashed by snow. And I would love to grow a Braeburn apple, but it usually won’t mature within our growing season. Natives, of course, are well-adapted to our conditions, but so are many other plants.

Then there is the theme of right-plant-in-the-right-place. A Russian Sage is bullet-proof, right? Not if you plant it in the shade. And iceplants that love sun may melt if they get too much hot late afternoon sun. So plants need to be given conditions specific to their natures or they will be stressed and diseased, attract pests, look bad or die. This is part of the challenge and fun of gardening: we have to get to know our plants and nurture them in the right way, even if that means reducing the water or fertilizer.

Another theme of organic/sustainable gardening is monitoring pests and diseases and evaluating them. Although it is another job to learn to recognize different insects and diseases, it is also part of the magic of creation which we get to tune into. When we learn to tell the difference between a rose slug and a ladybug larva, it can help us to see when nothing needs to be done, because Nature is taking care of the pests. And we can learn to not panic at the mere presence of a pest; we can look to see if the damage level merits intervention. I purposely leave small populations of pests in my garden to attract and feed beneficial insects.

Controlling pests brings up another organic theme which is: If damage levels are too high to be tolerated, use the least toxic, least invasive method that will support you plants. Some diseases can be eliminated by reducing water or by watering in the morning so the soil can dry before nightfall when humidity can condense on leaves. Some insects can be blasted off with a strong stream of water. Some sucking insects can be discouraged by spraying the leaves with seaweed (kelp) which toughens the leaf surface. Home-made (and commercial) sprays made from chili powder, garlic, eucalyptus etc can repel insects.

When pests need to be killed, my favorite method is horticultural oil. It is a mechanical pesticide, meaning that it is not at all poisonous and acts by coating soft-bodied insects with oil and suffocating them. It must be sprayed on the pest to be effective. I like this control because it has no effect on beneficial insects, bees, birds or soil organisms. I like the Pure Spray brand because it can be sprayed on the leaves without any burning. Horticultural oils cannot be sprayed over water with fish.

Insecticidal soaps are also popular because of their very low toxicity and negligible environmental impact. They act by dessication and must be sprayed directly on the pest to be effective. Both insecticidal oils and soaps may have to be reapplied to reduce larger populations and egg hatches. There are many Neem products that vary greatly in their strength. Neem works as an anti-feedant and disrupts insect development. It can be effective also against powdery mildew. Neem is an active ingredient in my toothpaste, so it has a very low toxicity when applied as directed.

Although it breaks down very quickly, I don’t recommend using Pyrethrum since even the powdered flowers of the Pyrethrum daisy are quite toxic, effecting beneficial insects and even cats. The synthetic pyrethrins and pyrethroids are more potent and longer lasting and therefore more dangerous. There are so many “soft pesticides” on the market that I can’t talk about all of them, but I am wary of Spinosad which effects the nervous system of insects and may harm bees.

Among the fungicides, the only one I recommend is Green Cure which is a potassium bicarbonate product, very similar to baking soda and not harmful to beneficial fungi in the soil. It is very effective, though the appearance may not change for a while. Even baking soda reduces some fungus problems, as does horticultural oil. Many fungus problems can be controlled culturally by reducing water, watering in the morning, using drip irrigation instead of overhead watering, improving air circulation or light exposure, aerating the soil mechanically or adding soil amendments.

One of the best pest controls is a diverse population of plants that support beneficial insects. It is especially good to grow plants with clusters of small flowers that provide nectar. Stuart Hill, a professor at McGill University, once said, “An investment in seeds of plants that will flower through the summer will give more pest control than that same investment in pesticides.”

The least toxic herbicides are horticultural vinegar, certain soaps and clove oil products. These are all most effective on annual weeds sprayed on hot, sunny days. Some perennial weeds can be controlled when used on small weeds or with repeated applications. Boiling water works where no valuable plants are nearby, as in between flagstones. Flaming by scorching the leaves is effective, but uses propane. Hand weeding is most effective when done before weeds get big enough to feed their roots.

Roundup and the glyphosates are NOT nontoxic. It may be unrealistic to say “never use them”, but almost never use them. Problems with cracking bark have been linked to the use of glyphosates near woody plants, and Roundup has been shown to be extremely lethal to amphibians like toads and frogs. In addition between 1984 and 1990, glyphosate was the third most reported cause of pesticide illness among agricultural workers; and the most reported cause by landscape workers. (See the sidebar)

Last on my list of themes of organic and sustainable gardening is “a naturalistic attitude,” as opposed to a “control freak” attitude. Learn to accept a certain level of damage. Trying to dominate Nature with complete control is unrealistic and unfriendly. Being OK with 10%-20% damage will make your life much more relaxed and require less time and money spent on maintenance. From a little distance, it may not even be noticeable. It is important to understand that only a small percentage of insects and fungi are pests and many are beneficial. It is also good to recognize that gardens with bugs support birds and beneficial insects.

Our reward for using a non-toxic approach to gardening are gardens and landscapes we are not afraid to touch and eat and let the children play in. Our soils and plants are genuinely healthier and our food is more nutritious. We support a world environment that is healthier and more diverse, with fewer greenhouse gases and a more peaceful people. Instead of contributing to an environmental global crisis, organic gardening and farming are becoming part of the healing of our planet. 


Roundup and Glyphosates

Since it was introduced in 1974 by Monsanto, it has been applied to more land area than any other active ingredient. This may be due to the advertised perception that it is essentially harmless since it biodegrades so quickly. It is my understanding that the safety of Roundup was based on tests performed on glyphosate alone, and it is coming to light that other ingredients added to these herbicides are responsible for some of the dangerous side-effects. Hannah Mathers, Ohio State University nursery and landscape specialist, tested many glyphosate products and discovered that it is the surfactants, known as “adjuvant loads” that cause bark splitting of woody plants if sprayed within 30’ of their trunks. This can be a serious problem since it takes years to break down the chemical once it is taken up by the shrub or tree. Other problems associated with the use of glyphosate herbicides include witch’s broom, stunting, growth problems, dead branches, and death. Ms. Mathers recommends using glyphosate products that do not contain the adjuvant load: Backdraft, Campaign, Expert, Extreme, Fallowmaster, Fallow Star, Fieldmaster, Glypro, Landmaster BW, Land Star, ReadyMaster Atz, Rodeo, Roundup Custom, and RU SoluGran.

In addition the Weed Science Society of America has warned that overuse of glyphosate has led to resistance in nine species of weeds, requiring higher doses for control or lacking any control. Their conclusion is that we need to find other methods of control.

And as mentioned in the main article, between 1984 and 1990 glyphosate use was the most commonly reported cause of pesticide illness among landscape workers and the third most common cause among agricultural workers.

Other resources:

Pesticide Action Network

Audubon Society guide to home pesticides:

Beyond Pesticides:

(Also, Jane, the data about pesticide illnesses in my last paragraph came from a Heritage Rose Soc newsletter with no sources)