Sand has many uses in a vegetable garden, but the most important are its benefits as a soil component and as an aid in starting vegetables from seed.
Adding coarse sand to garden soil helps create gaps between other soil components by allowing excess water to drain away and by creating air pockets that allow plant roots access to oxygen, water and nutrients. However, too much sand can make soil dry and infertile.
Vegetable gardeners should always use coarse sand, such as bulk or bagged sand found at home and garden centers labeled as builder's or yellow sand. Do not use fine white or beach sand, which makes soil less workable.
The term "soil conditioner" refers to any material that improves soil workability. A common recommendation for incorporating coarse yellow sand is to work in 1 to 2 inches of coarse sand and 3 to 4 inches of organic material per 100 square feet of garden.
Clay soils, while rich, are often unsuitable for vegetable gardening because of their poor drainage characteristics. Some clay soils can be improved by adding proper amounts of coarse sand and organic matter, though opinions differ on the practicality of amending heavy clay soils with the volumes of sand required to make it workable.
Seed Germination Aid
Gardeners can ease the process of sowing tiny seeds, such as carrots seeds, by mixing in coarse sand beforehand. Large-grained sand is also a useful non-soil germination aid: adding sand to the drill hole helps improve germination of beans, tomatoes and peppers by increasing the light and air reaching a seed.