How Much Gravel for a 12x20 Greenhouse Floor?
A 12 by 20 foot greenhouse covers 240 square feet. At 3 inches of gravel, plan on 2.22 cubic yards, or about 3.1 tons, which answers how much gravel for a 12x20 greenhouse floor.
Volume and tonnage calculator →The math
- Area: 240.0 sq ft.
- Depth in feet: 3 ÷ 12 = 0.250 ft.
- Cubic yards: 240.0 × 0.250 ÷ 27 = 2.22 yd³.
- Tons: × about 1.4 tons per yard = 3.1 tons.
The gravel calculator does this for any size.
Related: How Much Crushed Stone for a 12x20 Greenhouse Floor?
Gravel needed by depth
| Depth | Cubic yards | Tons of gravel | Tons +10% |
|---|---|---|---|
| 2 in | 1.48 | 2.1 | 2.3 |
| 3 in | 2.22 | 3.1 | 3.4 |
| 4 in | 2.96 | 4.1 | 4.6 |
| 6 in | 4.44 | 6.2 | 6.8 |
Stone for a greenhouse
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.
Related: How Much #57 Stone for a 12x20 Greenhouse Floor?
Prep
Clear vegetation, rake the soil level and compact it. Lay fabric overlapped at the seams and set edging before spreading the stone.
Buying the stone
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. Gravel is a broad label, so confirm whether the yard means crushed or rounded stone and whether it carries fines. The scale ticket is the real weight; tons per yard here is a planning figure.
Planning the cost
Stone is usually priced per ton or per cubic yard, and delivery is often a separate charge based on distance. A full truckload can cost less per ton than a partial one, so it can pay to combine projects. Ask whether the quote includes tax, delivery and any small-load fee before you compare yards.
Measuring the area
Use a long tape and measure each side twice. If the ground slopes, measure depth at the high and low ends and average them. Irregular outlines can be broken into simple rectangles, triangles and circles; add the pieces for the total square footage before converting to tons.
Questions people ask
How many tons of gravel for a 12x20 greenhouse floor?
About 3.1 tons at 3 inches deep.
How many yards of gravel for a 12x20 greenhouse floor?
About 2.22 cubic yards.
How many tons of gravel 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.
Related guides
- Gravel for a Greenhouse Floor: Best Stone, Depth and Tons
- How Much Does a Ton of Gravel Cover? Depth Chart
- Tons to Cubic Yards for Gravel: Conversion Chart
- Crushed Stone vs Gravel: Differences and Best Uses
- Geotextile Fabric for Driveways: Woven vs Nonwoven and How Much You Need
- Compacting a Driveway Gravel Base in Lifts
- How Much #57 Stone for a 12x16 Greenhouse Floor?
- How Much Pea Gravel for a 12x20 Greenhouse Floor?
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