Raised Bed Soil Mix Cost Calculator

Budget your raised bed soil before buying materials.

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How to Calculate Raised Bed Soil Mix Cost

Filling a raised bed with quality soil is the single biggest upfront cost in a kitchen garden. Knowing your volume and material ratios before you shop helps you avoid overspending — or worse, running short mid-project.

Step 1 — Find Your Bed Volume

Multiply the length by the width by the depth (converted to feet) to get cubic feet. Then divide by 27 to convert to cubic yards, which is how bulk materials are priced:

Cubic yards = (L × W × D in inches / 12) ÷ 27

A classic 4 × 4 × 12-inch bed holds about 0.59 cubic yards — roughly two to three large bags of bagged mix or a single small bulk delivery.

Step 2 — Choose a Soil Blend

Mel's Mix (popularized by Square Foot Gardening) uses equal thirds of compost, coarse vermiculite or perlite, and blended topsoil. It drains well, never compacts, and is ideal for intensive planting. It is also the most expensive option because perlite and vermiculite cost significantly more per yard than straight topsoil.

A budget blend of 60% quality topsoil, 30% compost, and 10% perlite costs noticeably less while still providing good drainage and fertility. It works well for less intensive crops like lettuce, herbs, and root vegetables.

Step 3 — Price Materials

Call local landscape supply yards for bulk cubic-yard pricing — it is typically 30–50% cheaper than buying bagged product at a big-box store. Many will deliver a minimum of one to two yards, often with a flat delivery fee. For very small beds, bagged topsoil and compost from a garden center may be more practical.

Typical Price Ranges (2025)

  • Topsoil: $20–$45 per cubic yard bulk; $5–$8 per 1-cu-ft bag
  • Compost: $35–$65 per cubic yard bulk; $8–$12 per bag
  • Perlite / Vermiculite: $80–$150 per cubic yard; $15–$25 per large bag

Multiple Beds

If you are filling several beds at once, total all the volumes together and price them as a single bulk order. You will almost certainly hit a price break and reduce per-yard cost significantly. The calculator handles one bed at a time, but you can scale the volume result by the number of beds you plan to fill.

Frequently Asked Questions

What is Mel's Mix for raised beds?
Mel's Mix is a soil recipe from the book Square Foot Gardening by Mel Bartholomew. It combines equal thirds of blended compost, coarse vermiculite (or perlite), and topsoil or a commercial mix. It stays loose, drains well, and supports dense planting without compaction. It is more expensive to fill initially but requires less amendment over time compared to ordinary garden soil.
How many cubic yards do I need for a 4x8 raised bed?
A 4-foot by 8-foot bed that is 12 inches deep holds 32 cubic feet, which equals about 1.19 cubic yards. At 6 inches deep the same bed holds roughly 0.59 cubic yards. Always add 5–10% extra to account for settling — soil compresses over the first watering season.
Is bulk soil cheaper than bagged?
Yes, in most cases. Bulk landscape supply yards typically charge $25–$65 per cubic yard depending on the material, while bagged products at retail stores can cost the equivalent of $150–$300 per cubic yard. For any bed larger than about 1 cubic yard, calling a local landscape supplier for bulk delivery is almost always the better value — factor in a one-time delivery fee of $40–$80.
Can I use perlite instead of vermiculite?
Yes. Both improve drainage and aeration. Perlite is a volcanic glass that is very light and inert — great for drainage-focused mixes. Vermiculite is a mineral that also retains some moisture and nutrients, making it slightly better for water retention in dry climates. Either works in Mel's Mix; perlite is usually more widely available at bulk suppliers.
How deep should my raised bed soil be?
Most vegetables do well with 10–12 inches of quality growing mix. Deeper-rooted crops like carrots, parsnips, and tomatoes prefer 18 inches or more. Shallow herbs and lettuce can thrive in as little as 6 inches. The calculator works for any depth — enter your actual bed depth in inches and it will compute the correct volume automatically.