Soil calculator for North Dakota

A 4 x 8 raised bed with a 12 inches fill depth contains 32 cubic feet of material. That works out to 1.2 cubic yards, more than many people expect when they start with a few bags in mind. Use the calculator for any planter, bed, or yard area and select from three soil types. Soil choice changes the weight: garden soil runs about 2,000 lb per cubic yard, screened topsoil 2,200, and fill dirt 2,400. Choose the material for your order to get the correct ton total.

Three steps for bed math

1. Enter each planter or bed measurement in feet. Multiple-areas mode combines all bed totals as you go.
2. For existing beds, use 4-6 inches. Use 6 inches for a new bed at ground level, or 12 inches to fill a raised planter from empty.
3. Divide cubic feet by 27 for cubic yards. Multiply yards by 1.0 to 1.2 for tons, based on your soil choice.

Coverage and weights

Choose soil for the work

• For vegetables, flowers, and planters, use garden soil blended with compost for planting.
• For lawns and final grading, choose screened topsoil. Use the Topsoil Calculator for lawn-depth guidance and sample calculations.
• For grade adjustments and low spots, use fill dirt as the base and keep quality soil for the planting layer.
• If native soil is worn out, work 2-3 inches of garden soil through the upper 6 inches instead of replacing the full bed. It costs less, and roots adjust more easily.

Fill raised beds for less

A deep raised bed does not need planting mix from bottom to top. When a bed exceeds 18 inches, use fill dirt or coarse organic material that breaks down in place for the lower portion. Put 8-12 inches of garden soil at the surface where plants root. Calculate each layer separately. Measure the 12 inches instead of estimating.

Example: three 4 x 8 beds

Order 4 yards for a 96 square foot bed filled 12 inches deep. The volume is 96 cubic feet, equal to 3.6 cubic yards, with an estimated 3.6 tons of garden soil. Blended material can settle roughly 10% in the first weeks as its compost content compacts. Use the extra material to bring the beds back to level after that initial settling.

Improve clay or sand in place

Clay holds water too long, while sand lets it escape before plants can use it. In either case, mix 2-3 inches of garden soil blended with compost through the top 6 inches, then do it again over a couple of seasons. That uses a third as much material and lifting as replacing everything. As roots and worms move through the soil, they continue carrying the blend downward. Reserve a full-depth soil swap for beds with construction debris or contamination in the native ground.

Bulk soil or bags

At 40 lb per bag, it takes about 36 bags to equal a cubic yard. A single raised bed can call for 43 bags, and moving 43 bags more than once is a lot of work. Bulk material costs less per cubic foot and comes in one tip, while free delivery avoids a truck fee to recover. Bags still make sense for one planter. Have the soil placed on a tarp because it can mark concrete, then cleanup is as simple as dragging and folding the tarp.

Soil amounts for beds and bags

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