Bags or bulk soil: what to compare before you order

Start with one required volume

Calculate the bed’s soil volume from inside dimensions and planned fill depth. Keep any optional extra soil in your order separate. That one requirement is the basis for both the bag and bulk option.

For a new layer across the ground, the topsoil calculator handles rectangles, circles and triangles, including an outline measured in parts.

Convert without rounding early: 1 cubic yard = 27 cubic feet. Whole bags are ceiling(required cubic feet ÷ labeled bag cubic feet). Bulk yards remain the calculated fraction until you enter the supplier’s actual order increment or minimum.

How much does a 40 lb bag of topsoil cover?

About 0.75 cubic foot of soil is in a 40-pound bag of topsoil, Michigan State University Extension’s garden hotline says, and the amount varies with how wet the soil is. Where the bag also prints cubic feet, use that figure instead.

At 0.75 cubic foot, one bag covers 9 square feet 1 inch deep, 3 square feet 3 inches deep or 1.5 square feet 6 inches deep. A 4 × 8 ft bed filled 12 inches deep holds 32 cubic feet: 43 bags, about 1,700 lb to lift into the car and carry to the bed. Past a few dozen bags, a bulk delivery usually saves the carrying. Mixing in compost? The soil mix calculator splits the bags by recipe.

Compare quantities before costs

For the 15-cubic-foot example, ten 1.5-cubic-foot bags exactly cover the amount the bed holds. The same volume is about 0.556 cubic yard. If a supplier’s minimum is 1 cubic yard, the delivered 27 cubic feet would be 12 cubic feet above the amount the bed holds before any extra soil you choose to order.

That does not make either option better. It exposes what must be compared: whole bags you can transport and store versus the bulk quantity the supplier will actually deliver and where it can be placed.

• Bag option: exact bag volume, whole bag count, unit amount, tax, and transport or delivery.
• Bulk option: quoted unit, minimum order, delivered quantity, delivery fee, drop location, and access limits.
• Both: material description, source, test or analysis when offered, and a plan for any amount above the fill requirement.

Make sure the materials are comparable

A bag called “garden soil,” “raised-bed mix,” or “organic soil” is not automatically equivalent to bulk topsoil or a topsoil-compost blend. University of Maryland Extension notes that many bagged organic-soil products contain combinations of wood products, compost, peat, and other materials rather than mineral topsoil.

For bulk topsoil, Maryland Extension recommends a reputable supplier and reviewing soil-test information and origin. Keep that advice in its jurisdictional context: the useful action anywhere is to compare the seller’s actual material description and available analysis, rather than treating the word “topsoil” as a specification.

Count the work after delivery

A bulk quote is incomplete without minimum order, delivery fee, drop location, and access constraints. A bag quote is incomplete without the whole-bag rounding and the handling or delivery needed to reach the beds. Blank fees remain unknown, not zero.

Do not place bulk material where it blocks drainage, traffic, utilities, or access. Do not use the calculated soil volume to approve the load on a deck, balcony, roof, or elevated structure.

Compare the whole cost

Use bagged material when its exact labeled volume, whole count, handling, and material specification fit the job. Use bulk when the quoted delivered amount, minimum, placement, and material specification fit. Cost is comparable only after every required field for both options is present.

Open the bagged vs. bulk soil cost calculator to compare whole-bag costs with bulk minimum orders, delivery charges and other required costs. Use your measured fill volume and confirm the supplier’s delivery access and drop location before ordering. Saving keeps the bed measurements and planning choices on this device; private prices and delivery quotes are excluded.

References

• Soil to Fill Raised Beds, University of Maryland Extension.
• Amount of top soil to purchase (Ask Extension answer #405905), Michigan State University Extension, on Ask Extension.