How Much Crushed Stone for a 12x12 Greenhouse Floor?

A 12 by 12 foot greenhouse covers 144 square feet. At 3 inches of crushed stone, plan on 1.33 cubic yards, or about 1.9 tons, which answers how much crushed stone for a 12x12 greenhouse floor.

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The math

Area: 144.0 sq ft.
Depth in feet: 3 ÷ 12 = 0.250 ft.
Cubic yards: 144.0 × 0.250 ÷ 27 = 1.33 yd³.
Tons: × about 1.4 tons per yard = 1.9 tons.

The crushed stone calculator does this for any size.

Crushed stone needed by depth

Depth	Cubic yards	Tons of crushed stone	Tons +10%
2 in	0.89	1.2	1.4
3 in	1.33	1.9	2.1
4 in	1.78	2.5	2.7
6 in	2.67	3.7	4.1

Building the greenhouse base

Greenhouse floors need to drain. A few inches of washed stone over landscape fabric keeps roots and weeds down and dries quickly after watering. Avoid stone with a lot of fines, which can turn muddy.

Before the stone goes in

Remove sod and roots, level the area and slope it slightly for drainage. Install edging so the stone stays inside the footprint.

Getting it delivered

Small dump trucks commonly carry around 5 to 10 tons and tri-axles more, but loads vary by truck and state, so ask the yard what fits in one trip. Crushed stone has angular faces that lock together under a compactor, which is why it holds a pad shape. Round up by about 10 percent for compaction and uneven ground.

Planning the cost

Quarries and landscape suppliers set their own prices, and they change by region and season. Get the price per ton, the delivery fee and the minimum order. If two products will both work, compare cost per square foot at your depth rather than cost per ton.

Common mistakes

The most frequent problem is ordering for the finished depth without allowing for compaction, which can shrink a loose layer by 10 to 20 percent. Another is skipping fabric on soft soil and watching the stone vanish into the mud over the first wet season. Spreading everything in one thick layer instead of compacted lifts also leaves a soft, rutted surface.

Questions people ask

How many tons of crushed stone for a 12x12 greenhouse floor?

About 1.9 tons at 3 inches deep.

How many yards of crushed stone for a 12x12 greenhouse floor?

About 1.33 cubic yards.

How many tons of crushed stone are in a cubic yard?

Roughly 1.4 tons for planning, but suppliers vary with stone size and moisture.

Should I put landscape fabric under the stone?

On soft or clay soil, a woven geotextile keeps stone from sinking into the dirt and makes the layer last longer.

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