How Deep Should a Raised Bed Be
Most vegetables do well in 8 to 12 inches of fill. Utah State University Extension says at least 6 to 12 inches, with no bottom on beds under 12 inches so...
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How Deep Should a Raised Bed Be
Plan on 8 to 12 inches of soil for most vegetables. Utah State University Extension says a bed should be at least 6 to 12 inches high. Beds under 12 inches should have no bottom, and the ground under them should be loosened 6 to 12 inches deep so roots can keep going.
On the Raised Bed Desk, the depth check reads the crops saved in My Garden and tells you the deepest bed they need.
Depth by Crop
This is a rule of thumb for beds on hard ground or a patio. Over loosened soil, roots grow past the frame.
| Depth | Crops |
|---|---|
| 6 inches works | Lettuce, spinach, radishes, arugula, mustard, green onions, basil, cilantro, chives, thyme, oregano, mint, strawberries |
| 8 to 10 inches | Beans, peas, peppers, cucumbers, eggplant, chard, kale, cabbage, broccoli, cauliflower, beets, onions, garlic, turnips |
| 12 inches or more | Tomatoes, carrots, parsnips, potatoes, squash, pumpkins, melons, okra, corn, asparagus, rhubarb |
Taller Is Not Always Better
- University of Minnesota Extension notes that for many gardeners, raising a bed more than a few inches is not necessary.
- Taller beds dry out faster and need more water.
- On pavement or in a very hot spot, a bed 1 to 2 feet tall keeps roots cooler.
- For wheelchair users, about 27 inches is a comfortable height.
- Tall beds cost a lot to fill. A 4 by 8 foot bed 24 inches deep holds 64 cubic feet of soil.
Width and Length
Make a bed narrow enough to reach the middle without stepping in. That is 3 to 4 feet wide if you can reach both sides, or about 2.5 feet against a fence or wall. Boards 6 feet or shorter are less likely to warp.
Related
- How much soil to fill a raised bed
- What soil to fill a raised bed with
- How many hours of sun your bed gets
Sources: Utah State University Extension, Raised Bed Gardening; University of Minnesota Extension, Raised bed gardens.