Raised beds: soil, spacing and what to plant
Build raised beds 6 to 12 inches deep (24 inches for wheelchair access) and no more than 4 feet wide, and fill them with half compost and half garden soil or topsoil (University of Illinois Extension). A 4×8 raised bed 12 inches deep needs 32 cubic feet of soil: 16 bags of 2 cubic feet, or about 1.2 cubic yards.
Tools
- Raised bed planner Bed size and ZIP code: how many of each crop fit, and what to plant now in your town.
- Soil calculator Cubic feet, cubic yards and bags for any bed.
- Vegetable spacing chart USDA's distances for 56 crops.
- How deep should a raised bed be? 6 to 12 inches, with the soil each depth needs.
Soil by bed size
- 2×4 bed8 cu ft at 12 in
- 2×6 bed12 cu ft at 12 in
- 2×8 bed16 cu ft at 12 in
- 3×3 bed9 cu ft at 12 in
- 3×6 bed18 cu ft at 12 in
- 4×4 bed16 cu ft at 12 in
- 4×6 bed24 cu ft at 12 in
- 4×8 bed32 cu ft at 12 in
- 4×12 bed48 cu ft at 12 in
- 8×8 bed64 cu ft at 12 in
Sources: Ken Johnson, University of Illinois Extension, “Raised Bed Gardening” (July 2023); USDA Home and Garden Bulletin No. 9 (1967), “Suburban and Farm Vegetable Gardens,” table 2.
Updated