Well drained soils of loamy texture provide the most favorable conditions for a vegetable garden. Sandy loam soils that are well-supplied with organic matter are easily worked and are quite productive. These are ideal conditions and you may have to make some adjustments to achieve such soils.
Clay soils are hard to work with and remain wet long after the rainy season and tend to form a hard crust. Sandy soils dry out rapidly and are easy to till but difficult to maintain at a high level of fertility. Both of these conditions must be modified for a successful vegetable garden; go to “Composition of Sandy Loam Soil” on this site for tips on how to make these necessary adjustments.
You must have the primary nutrients used by plants which are nitrogen, phosphorus and potassium. Nitrogen is largely responsible for healthy leaf and stem growth and is made available to plants by nitrogen fixing bacteria which convert nitrogen into nitrates. Nitrogen is rapidly used up by your plants and by decaying matter in the soil. It is easily washed out of the soil during heavy rains or over watering. An excess of nitrogen will cause excessive foliage growth stealing from the flowers and fruit.
For strong healthy roots phosphorus is very important, therefore flowering bulbs and root crops thrive with adequate phosphorous. This is why you will see fertilizers with a high phosphorous content advertised as flower boosters.
Potassium is your basic ingredient for overall plant health and it keeps the plants growing and aids their immune systems. Because it is water soluble, like nitrogen and potassium it needs to be replenished from time to time.
During the off season you want to use what is called a “Cover Crop” to prevent soil erosion and add organic matter. Garden soils benefit by being protected by a cover crop such as rye or rye grass.