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🌱 Raised Bed Soil Calculator
Calculate the exact volume of soil to fill any raised garden bed — cubic feet, cubic yards, bag count, and cost.
📐 Enter Your Dimensions
in
💡 Standard raised beds: 6–12" deep
$/cf
📊 Your Results
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Cubic Feet
Cubic Yards—
40 qt Bags (1.5 cu ft)—
2 cu ft Bags—
Total Area—
Estimated Cost
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Typical cost: $0.50–$1.20 per cu ft. Prices vary by region.
How to Calculate Raised Bed Soil
Building a raised garden bed is one of the most rewarding DIY projects — but ordering the right amount of soil makes the difference between a garden that thrives and one that struggles. Raised beds require good-quality, well-draining soil that won't compact over time.
The Formula
Volume (cu ft) = Length × Width × (Depth ÷ 12) × Number of Beds
Example: Two 4×8 beds at 12 inches deep: 4 × 8 × 1 × 2 = 64 cu ft = 2.37 cu yd.
Best Soil Mix for Raised Beds
The most popular mix is the "Mel's Mix" from Square Foot Gardening: ⅓ compost, ⅓ peat moss or coconut coir, ⅓ coarse vermiculite. This creates a lightweight, nutrient-rich, never-compact growing medium — ideal for vegetables.
Recommended Depths
- Herbs and leafy greens: 6–8 inches
- Tomatoes and peppers: 12 inches
- Root vegetables (carrots, beets): 12–18 inches
- Strawberries: 8–10 inches
- Perennial flowers: 8–12 inches
📦 Bags vs. Bulk
1 cubic yard = 27 cubic feet. A 40-quart bag ≈ 1.5 cu ft. For beds over 2 cubic yards, bulk delivery is much cheaper: $25–$60/yd³ vs. $80+/yd³ in bags.
✅ Add 10%
Soil settles after watering, especially in the first season. Order 10% extra or plan to top-dress with compost each spring.
🌱 Soil vs. Potting Mix
Never use native garden soil in raised beds — it's too heavy and can introduce weeds and disease. Use a purpose-blended raised bed mix.
📏 Common Bed Sizes
4×4 at 8": 10.7 cu ft | 4×8 at 12": 32 cu ft | 4×12 at 12": 48 cu ft | 8×8 at 12": 64 cu ft
Frequently Asked Questions
A 4×8 foot raised bed at 12 inches deep requires 32 cubic feet (1.19 cubic yards) of soil. At 8 inches deep you need 21.3 cubic feet. Use our calculator above to enter your exact dimensions.
The gold standard is ⅓ quality compost, ⅓ peat moss (or coconut coir), and ⅓ coarse vermiculite or perlite. This drains perfectly, never compacts, and is rich in nutrients. Pre-blended 'raised bed soil' from garden centers is a convenient alternative.
It's strongly discouraged. Native garden soil compacts under irrigation, drains poorly in containers, and often carries weed seeds, diseases, and clay particles that choke root growth. Always use a purpose-made raised bed mix.
Add 1–2 inches of compost to the top of your raised bed each spring before planting. Over 2–3 years, you may need to top-dress with 2–4 inches of fresh mix as the organic matter decomposes and the volume drops.