Your Organic Gardening Primer
Lesson 1: From the ground up
Organic gardening is a science based on being able to supply nutrient needs and ideal growing conditions that will produce healthy plants that can resist diseases and pests. Fruit and vegetables free of pesticides are considered healthier because they are untouched by man-made chemicals with the potential to cause health problems.
Success in growing plants organically begins with selecting land that can generate ideal growing conditions. Site and soil are of utmost importance. Establishing an organic garden on a slight slope facing south gives you soil that warms more rapidly in the spring and stays warmer in the fall than soil on a northern slope. A warmer soil will release nutrients from organic soil matter faster. Sandy soil will warm faster than silt or clay soil because there is less water present and the soil is denser. However, during drought, sandy soils will need supplemental irrigation and/or mulch to satisfy the water needs of the plants.
Full sun also helps warm the soil, enabling the release of nutrients from organic matter and maximizing photosynthesis.
Well-drained soils are essential to promote deep rooting of plants and early warming of soils. Avoid poorly drained soils. Good air drainage is essential for the rapid drying of foliage to minimize disease problems.
Since the organic content of the soil is the primary source of nutrients for plants, the pH measurement of soil acidity should be monitored by regular soil testing at three-to-five-year intervals. Soil testing is also a guide to maintaining optimum levels of nutrients such as calcium (Ca) and magnesium (Mg) and to prevent phosphorus (P) and manganese (Mn) from accumulating in excessive amounts.
The organic garden thrives on organic matter. To be successful, you need to increase the organic matter of the soil to five percent and above. For every percent of organic matter present in soils, 10 pounds of nitrogen (N) is generated per acre per year through a biological process known as mineralization. To obtain optimum yield, you must maintain the organic matter content of the soil at between five and 10 percent. Maintaining levels of organic matter concentration above five percent requires yearly applications of organic matter. Good sources include compost, animal manure and organic fertilizers such as fish emulsion, cotton seed meal, bone meal and compost tea.
In choosing seeds, the organic gardener seeks varieties with vigorous growth characteristics and disease resistance. In planting, avoid over-crowding, which increases competition among plants for sunlight and moisture. Crowded plants are more susceptible to diseases because they tend to be weak and their foliage is likely to remain wet for prolonged periods of time.
Healthy plants are more resistant to diseases than weak plants. However, healthy plants are equally susceptible to insect damage, though they are better able to tolerate limited plant damage before significantly reducing yields.