How much compost do I need for lawn topdressing?
At ¼ inch depth, you need about 0.77 cubic yards per 1,000 square feet. For a 2,500 sq ft lawn at ¼ inch, that is about 1.9 cubic yards, or roughly 26 bags of 2 cu ft compost. At ½ inch, double these numbers. Most extension services recommend ¼ to ½ inch and warn that more than ½ inch can smother existing grass.
Bags vs bulk compost — which is cheaper?
Bulk compost is far cheaper for anything over about half a cubic yard. A cubic yard of bulk screened compost typically costs $35-60 delivered. The same volume in 1 cu ft bags at $5-8 each costs $135-216. For small touch-ups under ½ cubic yard, bags are more convenient. Above that, bulk almost always wins.
How deep should compost be for lawn topdressing?
Penn State Extension recommends ¼ to ½ inch of screened compost spread after core aeration. More than ½ inch in a single application can smother grass crowns and block sunlight. For overseeding, ¼ inch provides a good seedbed without burying seed. Apply in spring or fall for best results.
What ratio of compost to soil for a raised bed?
A common raised bed mix is about 25-35% compost blended with topsoil and other amendments (like perlite, vermiculite, or coconut coir). For a 4×8 ft bed filled 10 inches deep, that means about 8-11 cubic feet of compost out of roughly 27 cubic feet total. Never fill a raised bed with 100% compost — it compacts badly, holds too much water, and can burn roots.
Can I use 100% compost in my raised bed?
No. Pure compost holds excessive moisture, lacks the structure roots need, can burn seedlings if not fully cured, and settles dramatically. Always blend compost with topsoil or potting mix — the compost portion should be about 25-35% of the total volume for vegetables and flowers.
How do I calculate cubic yards from square footage?
Multiply your square footage by the depth in feet (inches divided by 12), then divide by 27. Example: a 200 sq ft bed at 2 inches deep is 200 × (2 ÷ 12) ÷ 27 = 1.23 cubic yards. If the math seems tricky, use the calculator above to get the answer directly.
How much area does one cubic yard of compost cover?
At 1 inch deep, one cubic yard covers 324 square feet. At 2 inches deep, it covers 162 square feet. At 3 inches, 108 square feet. At ¼ inch (lawn topdressing), one cubic yard covers about 1,296 square feet. The calculator shows this breakdown for your specific depth.
When should I apply compost to my lawn or garden?
For lawns, early spring or early fall after core aeration are best — mild temperatures help the turf recover. For vegetable beds, apply and work in 1-2 inches in spring before planting, or in fall as a soil-improving mulch. For trees and shrubs, apply a 2-3 inch ring in spring, keeping compost away from the trunk.