Thursday, September 13, 2012

Patience with Garden Pests: Part 1 - Cultural Control

Today I would like to talk about pests in the garden. Absolutely nothing is more frustrating to gardeners than waking up to find that your prized pumpkins have wilted or finding that your tomatoes have been marauded by hungry birds the exact morning you planned on picking them. Somehow they always know! I can't think of anything that tests the resolve of organic gardeners more than facing the fact that the best course of action may be digging up an infested plant and starting over next year.  Unfortunately this is not always avoidable. But fear not my friends! I am here to tell you that it is possible to get the upper hand on crawlers and critters without having to resort to harsh poisons or lethal traps.

"An ounce of prevention is worth a pound of cure." 

For most people, the sight of any insect in the home or garden is cause for alarm. The first instinct for most of us is to reach for the can of insect killer or call the exterminator. Organic gardeners are not free of blame, I've seen plenty of well-intentioned folks reach for the insecticidal soap or DE because of a few ants and aphids with out any regard for what impact those products will have on the garden ecosystem. As organic gardeners we sometimes lose sight of the fact that just because some products are safer than their synthetic counterparts it does not mean that they are 100% safe. Some are highly toxic to aquatic life, others to pollinators like bees. They can also be harmful to the beneficial insects we rely on to keep pests in check. For these reasons sprays and dusts must always be a last resort

The first step in pest management is to begin with proper Cultural Control. Cultural control is the practice of modifying the growing environment to reduce the prevalence of unwanted pests. Healthy soil that is alive with microbes, fungi, earthworms, and other organisms is the foundation of organic gardening. Growing plants in healthy soil not only enables them to withstand any insect assault that may come their way, but healthy, well nourished plants are actually unappealing to most insects. Sickly plants as well as plants that are over nourished with synthetic nitrogen  fertilizers will actually attract insects. You can achieve even more garden success by choosing  and planting insect and disease resistant varieties and timing their plantings so that they do not coincide with the feeding cycle of their particular pest insect. This concept is known as timed planting. If critters are your problem, the solutions may be as simple as planting a little extra to share, or as complex as installing an electric fence around the whole garden, either way, there are many ways to modify your growing environment to prevent losing your valuable homegrown produce. 

Another cornerstone of organic gardening is the concept of intercopping or companion planting Companion planting is a fascinating subject that deserves a more in depth discussion but I will touch briefly on some of the more salient points. As a cultural control companion planting serves many purposes but essentially the primary function is to eliminate the presence of monocultures. A monoculture simply means a crop of only one variety planted in a particular area.  This is the most common type of farm you will see, fields of corn or wheat or soy beans as far as the eye can see. Growing plants of the same family close together in your home garden is also a form of monoculture. Pests flock to monocultures because there is so much available food in one place. Diseases spread rampantly and nutrients are robbed from the soil. Companion planting eliminates these problems and more. Herbs and flowers planted amongst your vegetables will help to attract beneficial insects and naturally enhance your Biological Control by providing food and shelter to lady bugs, lacewings, predatory wasps and spiders. In addition, the strong smell of many herbs and flowers act as a repellent to many garden pests. Other companions act as trap crops attracting pests that you can easily dispose of all at once. Borders of rabbit and dear resistant flowers can create a natural barrier that is both beautiful and functional. 

Many garden pests spend at least part of their life dwelling in the soil. For this reason, crop rotation is an essential cultural control. Because plants of the same family attract similar pests, is important that they are not planted in the same place year after year. For example, tomatoes should not be planted in the same place where you previously had planted eggplant or chilies. Cabbage should not be planted where you had Brussels sprouts or broccoli. Crop rotation also provides an opportunity to rebuild and re-nourish the soil. Legumes like peas, beans, clovers, oats, and vetches can take nitrogen out of the atmosphere and turn in into a form that is usable by plants. In addition, when dug into the soil at the end of the season, the bio-mass of these cover crops or green manures provides organic matter that will become a food source for soil micro-organisms that in turn will become a balanced food source for your plants.

The last step in proper cultural control is to maintain a clean garden free of weeds and other debris that may provide a shelter area for pests. Diseased and infested plants must be properly disposed of in a very hot compost pile, burned, or fed to chickens or other livestock so that no eggs or larvae survive. Plants should be heavily mulched, not just to conserve water, but to prevent soil borne diseases from splashing back onto the leaves where they can spread. Water at ground level when ever possible and as always remember, never let the mulch touch the base of the plant and never dig diseased plants back into the soil if you plan on planting within the next year.  

Well there you have it. I hope this provides a nice foundation for understanding where to start when dealing with pests in your garden. While cultural controls are a very important first step, they sometimes may not be adequate for the issues you may be dealing with. Next time we will deal with the Physical Control that will aid you in you battle against the pest nemesis! In the meantime, please check out some of the links below that have to do with some of the issues we talked about today. 

Happy Gardening!