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GARDENING IN GWINNETT: Organic vegetable gardening is all about the soil

Timothy Daly

Timothy Daly

Some of the most frequent questions we receive at the Extension office are on the subject of organic gardening. It is the combination of methods and strategies for the production of healthy plants based on a holistic view of the garden.

This view includes the surrounding landscape and the soil organisms as part of on overall system in balance with nature. The practice of organic gardening tends to be labor intensive. It requires an in-depth knowledge of the ecological relationships among soil, plants and animal organisms associated with the garden. It also requires considerable thought and planning. Contrary to popular myth, organic gardening is not simply a method of pest control nor is it just gardening without the use of synthetic pesticides and fertilizers.

A long-term outlook with respect to soil preparation is required when gardening organically. The goal is to feed the soil, not the plant. The development of healthy, fertile soil will provide the plants with the necessary nutrients they need. Whether you have heavy clay or light sand, you can take active steps to improve your soil quality and stimulate the health of your plants.

Organic gardeners use natural organic fertilizers and mineral amendments to improve the overall quality and fertility of the soil. Often synthetic fertilizers provide nutrients immediately available to the plant, but do nothing to improve the overall health and long term fertility of the soil. Organic matter in the soil is important because it breaks down and releases nutrients that crops can utilize. It improves the soil's water and nutrient-holding capacity as well as providing a habitat for microorganisms and counteracts topsoil erosion.

Organic matter in the soil can be increased by the addition of manure, topsoil, peat moss, compost, and other suitable materials. Consider having your soil tested through the Extension office in order to find out the soil nutrient and pH levels.

One way to control pest problems is to plant varieties with resistance to diseases and insects. Resistance, however, is seldom 100 percent. The plant may show some symptoms but they are usually less severe symptoms than susceptible varieties. For example, tomatoes have been bred to have resistance to Fusarium, and Verticillium fungal diseases and resistance to nematodes, a microscopic wireworm. Look for varieties that have the letters VFN on the labels to show their resistance.

Plants showing symptoms of diseases should be removed and disposed of. Reduce the incidence of disease by keeping the leaves and stems of the plants as dry as possible. Use drip irrigation rather than overhead to reduce the amount of time plants remain wet and also to conserve water. Insect control begins with healthy plants.

Buy insect- and disease- free plants. Timing is also important. Some insect pests tend to increase as the season progresses. Planting early can avoid many insect problems on certain vegetables, while other vegetables are better planted later. Encourage beneficial insects, like lady beetles, lacewings and certain species of wasps to stay in your garden. Certain herbaceous plants, such as dill, wild mustards, yarrow and others, provide shelter and food for these beneficial organisms and should be planted amongst your vegetables.

There are several organic pesticides available. Botanicals are plant-derived materials such as rotenone, pyrethrum, and Neem oil products. Microbial pesticides are formulated from microorganisms or their by-products that control certain insect pests.

Minerals such as sulfur and copper are the primary organic fungicides and bactericides used to prevent disease in the field.

Remember, if a product is considered to be organic, it is still a pesticide. Use caution when using them. An organic or natural pesticide does not mean that it is non-toxic.

Organic pesticides have specific modes of action, just like synthetic pesticides. Some organic pesticides are as toxic, or can be even more toxic, than many synthetic chemical pesticides. Remember arsenic is organic.

Timothy Daly can be e-mailed at timothy.daly@gwinnettcounty.com.