The best gardening soil is comprised of three different sized mineral particles: sand, silt, and clay. Coarse sand is used to make fertile garden soil and promotes the proper drainage necessary for growing healthy vegetables.
Coarse sand, also called builders sand, is the best type of sand to add to the soil in your vegetable garden. The sand should have sharp, not rounded, edges and be 0.5 to 1.0 millimeters in diameter. When mixed in with your soil, it will provide plants with proper drainage and it helps to prevent crown rot.
Bought in bags for children’s sandboxes, fine sand is not used in vegetable gardening. It does not increase soil drainage and provides no other benefits to the garden.
Salts in Sand
Beach sand may contain high levels of salt. When mixed into the soil, the salts in the sand will alter the pH balance of garden soil and can prevent plants sensitive to salts from growing or producing. Although beach sand can be washed to remove fine dust and salt, it is still not a good sand to use in gardening because it is too fine.
Adding Sand to Soil
When you have clay soil, water will often settle on top of the soil after a rain. Clay soil retains water and doesn’t provide plants with enough drainage and aeration to grow healthily. While it was formerly believed that adding coarse sand to the soil improved water drainage, soil experts now advise that adding sand does not improve the soil's quality. It is now recommended that organic matter is added to soils to improve the soil's quality. The addition of earthworms and other beneficial microorganisms will help improve the soil's texture.