Cover Crops - Cover crops, such as annual rye or wheat, planted in the garden in the fall, and tilled under in the spring, can also add organic matter and lessen the chance of groundwater contamination. A leguminous cover crop such as alfalfa or clover can also add nitrogen to the soil when tilled in. Cover crops, compost, and manures also add trace elements, which are essential for good growth, though only needed in small amounts. Fertilizers - Fertilizers for the garden may be either organic or synthetic. Both organic and synthetic fertilizers can be fast or slow acting.
Organic fertilizers can benefit long term soil conditions by increasing organic matter content.
Nitrogen is responsible in the plant for producing leaf growth and greener leaves. A deficiency causes yellow leaves and stunted growth. The second number, phosphorous, is important in seed and root development and fruit growth. Potassium, the third major element, promotes early growth, improves stem strength, and contributes to cold hardiness. In the vegetable garden, fertilizer may be incorporated into the soil either by broadcasting it over the entire garden, or by applying it in narrow bands on either side of the plants in the row.