4 × 12 ft bed: the short answer
Filled 10 inches deep, a 4 × 12 ft raised bed needs about 40.0 cubic feet of soil — that's roughly 27 bags of 1.5 cu ft (or 20 of the 2 cu ft size), and about 1.48 cubic yards if you order in bulk.
Bed size
Soil for a 4 × 12 ft raised bed
A 4 × 12 ft bed filled 10 inches deep takes about 40.0 cubic feet of soil — about 27 bags of 1.5 cu ft, or 1.48 cubic yards in bulk. Change the depth, bag size, or mix below for your exact build.
Soil needed
—Enter bed size and depth to estimate soil.
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Soil mix breakdown
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Shopping list
Run the calculator to prepare a list.
Estimate only.
Based on the bed volume you enter. Fresh soil and compost settle, so buying a little extra is
normal. Bag counts are rounded up; confirm against your supplier's bag coverage.
Before you buy
Soil and compost settle after the first few waterings, so buying one extra bag is sensible. If you need close to a cubic yard, compare bulk delivery — it's usually cheaper per cubic foot than bags. Adjust depth and bag size in the calculator for your exact build.
Standard volume math at 10″ depth; 1 cu yd = 27 cu ft. Estimates only.
What a 4 × 12 ft bed is usually used for
A 4 × 12 ft raised bed is a generous production bed for a backyard garden: large enough for full-size tomatoes, cucumbers, squash, and rows of greens while still staying reachable from both long sides. The bigger footprint makes fill planning and irrigation decisions the real project.
How to decide
At 48 sq ft and 10 inches deep, the fill approaches 1.5 cubic yards, so bulk delivery usually wins on cost and effort. Decide whether to fill the whole depth at once or top up over time, and set up drip or soaker irrigation before planting so water reaches the roots instead of running off the surface.
Checks before you fill
- Price bulk fill with delivery against dozens of bags before ordering.
- Plan irrigation before planting; a bed this long is hard to water evenly by hand.
- Confirm reach from both sides so tall plants do not block access to the middle.
FAQ
How much soil for a 4 × 12 ft raised bed?
At 10 inches deep, a 4 × 12 ft bed holds about 40.0 cubic feet of soil (1.48 cubic yards). In bags that's about 27 × 1.5 cu ft, or 20 × 2 cu ft. Deeper or shallower fills scale directly with depth — use the calculator above to match yours.
How many bags of soil for a 4 × 12 ft bed?
About 27 bags if you buy 1.5 cu ft bags, or 20 bags of the larger 2 cu ft size. Always round up — and add one extra bag, since compost settles after watering.
What's the Mel's Mix for a 4 × 12 ft bed?
Mel's Mix is equal thirds compost, peat moss or coir, and coarse vermiculite. For 40.0 cu ft that's about 13.3 cu ft of each — roughly 9 bags of 1.5 cu ft per component.
Sources & verification
Source links and page assumptions reviewed .
- Square Foot Gardening: Mel's Mix method — Defines Mel's Mix as equal volumes of blended compost, coarse vermiculite, and peat moss or coir.
Estimate only, based on standard volume math at 10″ depth. Real fill varies with settling and supplier bag sizes; bag counts are rounded up. Confirm against your supplier before ordering.