Raised Bed Soil Calculator
Enter the bed length, width and soil depth. The calculator gives cubic feet, the number of 1.5 cubic foot bags, the cost, and the two-inch top-up figure for beds that already exist.
The honest alternatives arrive at volume: landscape yards sell by the cubic yard at a fraction of bagged pricing - one yard covers about eighteen bags - and established beds skip the reset entirely in favor of a two-inch compost top-up that feeds the soil web better than replacement ever does.
How to use
- Measure inside the frame, length by width, and pick the depth.
- Twelve inches suits tomatoes and roots; six is fine for lettuce.
- Past six bags, call a landscape yard and price a cubic-yard delivery.
Frequently asked questions
How much soil do I need for a 4x8 raised bed?
At 12 inches deep, 32 cubic feet - about 22 of the 1.5 cubic foot bags. Six inches deep halves it to 16 cubic feet. The calculator prices either depth from your dimensions.
How many bags of soil for a raised bed?
Divide total cubic feet by 1.5 for standard bags and round up for settling. Past about six bags, a landscape yard delivery by the cubic yard costs a fraction of the bagged route.
What depth does a raised bed need?
Six inches runs lettuce, herbs and greens; twelve covers tomatoes, peppers and root crops; deeper beds mostly buy drainage and root-run for the ambitious. Deeper than your plants need is money spent on soil.
Do I need to replace raised bed soil every year?
No - top up with two inches of compost each spring instead. Replacement dumps a functioning soil web and costs the most; the calculator shows the top-up figure next to the full reset for the comparison.