Soil Calculator for Indiana Raised Beds and Planters
Enter your project dimensions
A raised bed on this ground is usually a way around the soil rather than an improvement to it. Where the native ground is dense till that stays cold and wet into May, a box of bought blend sitting above it gets roots working weeks earlier. That is what brings most people to the soil calculator, and it is also where the three soil products get tangled up, because the blend in the box, the growing layer on a lawn and the material that brings a low corner up to grade are three different orders with three different weights.
What the Tape Misses When a Bed Sits on Slow-Draining Till
The tool works out the volume of the box you describe. Everything that happens under the box is yours to judge.
- A bottomless bed set on unbroken clay will take more than its measured depth. The first watering pulls the blend down into whatever you loosened underneath.
- A bed with no drainage path under it holds water like a tub. Fork the ground through before the soil goes in, especially on flat sites where the surrounding yard has nowhere to drain to either.
- Blends settle. The compost fraction breaks down and loses height in the first weeks, which is volume you measured and paid for and will want back.
- Timber depth and soil depth are not the same number. A 16 in board with 2 in of freeboard at the top is a 14 in fill.
Weighing a Yard of Blend Against a Yard of Fill
The material select is what makes the tonnage right, because the three soils are not close in weight. This site publishes garden soil at about 2,000 lb per cubic yard, screened topsoil at about 2,200 and fill dirt at about 2,400, which the tool reads as 1.00, 1.10 and 1.20 tons a yard. Pick the wrong one and the cubic yards are still correct while the tons are out by a fifth.
Cubic yards are the figure that matters for soil, since that is how it is sold. Square feet times the depth in inches, divided by 12, gives cubic feet, and dividing that by 27 gives cubic yards. Coverage is worth carrying in your head as a check: one cubic yard spreads over 162 sq ft at 2 in, 81 sq ft at 4 in, 54 sq ft at 6 in, and fills 27 sq ft of raised bed at a foot deep.
For comparison with a shelf, a 40 lb bag holds around three quarters of a cubic foot, so roughly 36 bags make a yard. Once a job needs more than a dozen of them, the wheelbarrow is doing more work than the tape.
Where the Soil Calculator Needs an Inside Measurement
- Choose rectangle, circle or multiple areas. Multiple areas takes five beds or planters and adds them into a single total.
- Enter length and width in feet, measured to the inside of the boards. A round planter goes in by diameter.
- Enter the depth of soil in inches, from 0.25 to 24. Use 4 to 6 in when refreshing an established bed, 6 in for a new in-ground bed and 12 in to fill an empty raised box.
- Choose garden soil, topsoil or fill dirt so the weight is right.
- Tick the 5% box for spillage.
- Press calculate, read the cubic yards, and send yourself the figures with email my quote.
A bed deeper than 24 in will not go in as one entry. Split it, which suits how a tall box should be filled anyway.
Two Beds at Fourteen Inches and a Border That Only Needs Feeding
Both are examples with invented sizes, not customer projects.
Two 4 ft by 10 ft beds filled to 14 in with garden soil.
- 4 x 10 x 2 beds = 80 sq ft
- 80 x 14 / 12 = 93.3 cubic feet
- 93.3 / 27 = 3.46 cubic yards
- 3.46 x 1.00 = 3.5 tons
An established border, 240 sq ft, topped up 3 in.
- 240 x 3 / 12 = 60 cubic feet
- 60 / 27 = 2.22 cubic yards
- 2.22 x 1.00 = 2.2 tons
The border is the cheaper habit of the two. Working 2 to 3 in of compost-blended soil into the top 6 in of an existing bed, repeated over a couple of seasons, does more for a heavy clay border than lifting it out and replacing it, and it takes about a third of the material. Worms and roots carry the blend down from there. Full replacement is for ground spoiled by construction debris, not for ground that is simply tired.
Filling a Thirty-Inch Box Without Paying for Blend at the Bottom
Deep planters do not need growing soil all the way down. Feeder roots live in the top 8 to 12 in, so a tall box gets a cheaper lower layer and good soil above it. Take a 3 ft by 12 ft planter standing 30 in deep, again as an example:
- Area: 3 x 12 = 36 sq ft
- Lower layer, 18 in of fill dirt: 36 x 18 / 12 = 54 cubic feet, 2.00 cubic yards, 2.4 tons
- Upper layer, 12 in of garden soil: 36 x 12 / 12 = 36 cubic feet, 1.33 cubic yards, 1.3 tons
Two runs of the tool, two materials, one delivery date. The same split works with coarse organic matter in the bottom instead of fill, which breaks down in place and drops further as it goes.
The Tenth That Disappears Once the Compost Settles
Blended soil loses roughly a tenth of its height in the first weeks, and heavily composted mixes can drop 10 to 20%. Three things keep that from turning into a second order:
- Fill slightly proud of the rim, water it in hard, then top up once rather than three times.
- Order to the next sensible yard rather than the exact decimal. A part yard left over goes into pots or a thin spread on the lawn.
- Expect an inch or two a year in a planted bed. That is the compost doing its job, not a short delivery.
Which Job This Tool Is For, and Which Belongs Elsewhere
The split is by job rather than by product name, and it matters because the wrong tool returns the right volume at the wrong weight.
- Garden soil is the blend for raised beds, planters and planting areas. Size it here, at 1.00 ton a yard.
- Screened topsoil is the growing layer for lawns, seeding and finish grading. Size it on the topsoil calculator, at 1.10 tons a yard.
- Fill dirt is compactable subsoil for raising grade, backfill and the bottom of a deep planter. Size it on the dirt calculator, at 1.20 tons a yard.
Once the yardage is settled, open the product page, set the quantity and choose a delivery date. Delivery is arranged at checkout by ZIP code, and the truck needs firm ground to tip on, which in a wet spring means the drive rather than the lawn. Ask for the pile on a tarp; soil marks concrete and the tarp folds up at the end of the job.
Common questions
Same bed, different soil in the list, different tons. What changed?
Only the weight. The bed has one volume and the cubic yards prove it by not moving. Garden soil is published here at 2,000 lb a yard against 2,400 for fill dirt, so the same box comes out a fifth heavier in fill even though you are filling exactly the same space.
Does the 5 percent box earn its place on a raised bed?
It covers spillage and the first settling, which is worth having, but it will not cover what compost loses over a season. Tick it, fill proud of the rim, and plan on topping up once after the first few waterings.
Half the border runs along a bank. What goes in the length and depth boxes?
Measure the length across the ground as if you were looking down on it, not along the face of the slope, and average the soil depth between the high edge and the low edge. A border that is 2 in deep at the top and 6 in at the bottom is a 4 in entry.
The beds run around three sides of a patio. Can I total them in one go?
Yes, in multiple areas mode. Enter each run as its own rectangle, up to five in a single calculation, and the tool adds them. Splitting them also lets you give the shadier run a different depth if you are only refreshing that one.
The bed is boxed in with landscape timbers. Which face do I measure to?
The inside face, since that is the space the soil fills. Measure the depth from the ground level inside the box to where you want the soil to finish, leaving an inch or two of freeboard so watering does not wash the blend over the edge.
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