Soil Amending: Calculating Topsoil and Conditioner for Lawns and Gardens

Homeowners often want to amend existing soil. Planting grass seed or sod on hard, unfertile soil wastes money. For lawns, cover the area with good topsoil and till it into the bad soil underneath. Typically, spread 4 inches of topsoil. Soil is sold by the cubic yard: 3 cubic yards covers 1,000 sq ft at 1 inch thick; for 4 inches, you need 12 cubic yards per 1,000 sq ft.

Gardens

For gardens, mix soil amendment (Nature's Helper, Earth Helper) into soil to loosen it. Clay soil needs 2–3 inches of conditioner tilled 8 inches deep. Conditioner comes in 2 cubic foot bags—one bag covers 8 sq ft at 3 inches thick. Rule of thumb: 1 bag per 10 sq ft.

Calculate the Area

To know how much to buy, calculate your area. For squares/rectangles: length × width = square feet. Example: 12 ft × 10 ft = 120 sq ft. A lawn 110 ft × 50 ft = 5,500 sq ft. Exactness isn't necessary—close is fine.