If you will be filling more than one raised bed, you may want to buy your soil in bulk — by the cubic foot or cubic yard. Use the Soil Calculator to figure out the total amount of soil you'll need for each bed. For most situations, we recommend these proportions:
- 60 percent topsoil
- 30 percent compost
- 10 percent soilless growing mix (potting soil).
Example: How Much Soil Do I Need for a 3x6 Bed?
A 3x6 bed with 10" sides will need 15 cubic feet of blended soil. To create the blend, use the following quantities:
- 9 cubic feet of topsoil (nine 20-quart bags)
- 4.5 cubic feet of compost (four and a half 20-quart bags)
- 1.5 cubic feet of soilless growing mix
- 1.5 cups Complete Organic Fertilizer
Before placing your raised beds in their permanent location, be sure to remove any grass or perennial weeds from the area. Loosen the native soil with a shovel or garden fork to a depth of 6-10”. This will improve drainage and moisture retention in the raised beds. It also means that even with a 5″-high raised bed, your plants will think they're growing in a bed that's 12-18″ deep.
Where to Buy
We have a wide selection of cedar raised beds, raised bed corners perfect for a DIY raised bed project and elevated raised beds, as well as watering systems, pest protection, season-extending tools and accessories.
Keep in mind that proportions are approximations as soil volume varies from source to source. If the calculator specifies .435 cubic yards of soil for your bed, for example, round it up to a half yard.
Refresh an Existing Bed
- Remove any weeds
- Loosen and fluff the soil (winter snow and rain can compact it).
- If the soil has settled, top it off with an inch or two of fresh compost and mix it into the existing soil.
- Replenish nutrients and re-energize the soil with the Raised Bed Healthy Soil Booster Kit.
Gardener's tip: If you are not planting within a week, protect with soil with a layer of straw. This will, however, prevent the soil from warming up and drying out. So you'll need to uncover the bed at least a week before planting warm-season crops.
Recharge a Pot or Planter
For small pots, toss your old soil into the trash and start fresh with new planting mix. With larger planters, you can recharge the existing soil with Container Booster Mix from our friends at Gardener's Supply Company. Just mix in 4-8 tablespoons per quart of existing soil.