A sandbox is a great play space for small kids because it can be built easily and cheaply compared to most playground equipment and because it helps to stimulate creativity and encourage imagination. But once kids outgrow a sandbox, many homeowners aren't sure what to do with it. Sandboxes can be repurposed as a home landscaping or gardening project. A wide variety of lawn and ornamental grasses will grow in sand once it has been amended with additives to improve the soil structure.
Break up sand throughout the box with a spade and rake. Typical sandbox sand consists of washed sand. This sand is sold in hardware stores as play sand. Play sand contains no clay or loam and the texture is loose and fluffy. You should be able to break up the sand without resorting to heavy equipment such as a rototiller.
Spread a four-inch layer of loamy soil amendments over the sand. Good soil amendments include peat moss and compost. These amendments help the sandy soil retain moisture and will add nutrients that the grass uses to grow.
Mix the amendments thoroughly with the sand, using a rake and shovel. Turn the sand with the shovel to spread the amendments through the soil. Comb the surface with the rake to blend the sand evenly with the amendments.
Smooth the surface of the sand with the smooth side of the rake. Create furrows in the soil with the rake's toothed side.
Sprinkle grass seed evenly over the soil. Use a grass that sprouts well in sandy loam, such as Bermuda grass or zoysia in the subtropical regions of the South. Select a cold-season grass such as Kentucky bluegrass or rye grass for northern climates. Do not bury the seed. It will sprout wherever it comes in contact with the soil.
Water your sand up to four times daily with ¼ inch of water from a sprinkler. Use a rain gauge to measure the water amount. Taper off this watering cycle after 14 days until you only water the grass with one inch of water every 10 days.