How much soil for a 3×6 raised bed

A 3×6 raised bed 12 inches deep needs 18 cubic feet of soil: 9 bags of 2 cubic feet, or about 0.7 cubic yards.

Fill it with a 1:1 mix of compost and garden soil or topsoil (University of Illinois Extension): 9 cubic feet of each. Illinois Extension also notes the bed settles as the compost breaks down, so plan to top it up each year.

At 3 feet wide this bed is reachable from both sides, within Illinois Extension's 4-foot limit for beds you can walk all the way around.

Soil for a 3×6 bed (3 by 6 feet)
DepthCubic feetCubic yards2 cu ft bags1.5 cu ft bags1 cu ft bags
6 in90.33569
8 in120.446812
10 in150.5681015
12 in180.6791218
18 in271.00141827
24 in361.33182436

Cubic feet = length × width × depth in inches ÷ 12; cubic yards = cubic feet ÷ 27; bags rounded up. Bed sizes and fill: Ken Johnson, University of Illinois Extension, “Raised Bed Gardening” (July 2023). Soil calculator for any size.

What fits in a 3×6 bed

A raised bed has no rows, so we space plants the USDA in-row distance apart both ways, in a grid (our method, not USDA's). The range runs from USDA's widest to its closest spacing.

Plants that fit in 3 by 6 feet
CropSpacingPlants
Asparagus18 in8
Beets2–3 in288–648
Broccoli14–24 in3–10
Brussels Sprouts14–24 in3–10
Cabbage14–24 in3–10
Cantaloupe6 feet0
Carrots2–3 in288–648
Cauliflower14–24 in3–10
Celery4–6 in72–162
Chervil and Chives2–3 in288–648
Chinese Cabbage8–12 in18–36
Collard Greens1½–2 feet3–8
Corn Salad12 in18
Cucumbers3 feet2
Dandelion Greens8–12 in18–36
Eggplant3 feet2
Endive12 in18
Fennel4–6 in72–162
Garlic2–3 in288–648
Green Beans3–4 in162–288
Head Lettuce12–15 in8–18
Horseradish1½–2 feet3–8
Kale12–15 in8–18
Kohlrabi5–6 in72–98
Leeks2–3 in288–648
Lettuce6 in72
Lima Beans3–4 in162–288
Mustard Greens12 in18
New Zealand Spinach18 in8
Okra2 feet3
Onion Seed2–3 in288–648
Onion Sets2–3 in288–648
Onions2–3 in288–648
Parsley4–6 in72–162
Parsnips2–3 in288–648
Peas1 in2,592
Peppers1½–2 feet3–8
Potatoes10–18 in8–21
Radishes1 in2,592
Rhubarb3–4 feet0–2
Rutabaga2–3 in288–648
Salsify2–3 in288–648
Shallots2–3 in288–648
Sorrel5–8 in36–98
Soybeans3 in288
Spinach3–4 in162–288
Summer Squash (Zucchini)15–18 in8
Sweet Corn14–16 in8–10
Sweet Potatoes12–14 in10–18
Swiss Chard6 in72
Tomatoes1½–3 feet2–8
Turnips2–3 in288–648
Upland Cress2–3 in288–648
Watermelon2–3 feet2–3
Winter Squash2–3 feet2–3
Witloof Chicory6–8 in36–72

Spacing: USDA Home and Garden Bulletin No. 9 (1967), “Suburban and Farm Vegetable Gardens,” table 2. Plan this bed for your town · Spacing chart.

Updated