Plant Care

Best Soil for Raised Beds: 6 Commercial Mixes Tested and Compared

Last updated: October 30, 2025
Professional testing reveals which commercial soil mixes deliver the best drainage, nutrition, and value for raised bed gardening success.
MMike Thompson
October 30, 2025
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Commercial raised bed soil mixes being compared for texture and quality testing

— Image © PlantReference.org 2026
TL;DR
After testing six commercial raised bed soil mixes for 120 days, Miracle-Gro Organic Raised Bed Mix delivered the best combination of drainage, plant performance, and value at $10 per cubic foot. Back to the Roots Organic performed equally well but costs 30% more. Avoid generic topsoil blends—they compact severely and lack proper drainage for container growing. The best soil for raised beds requires 30-50% organic matter, excellent drainage, and pH between 6.0-7.0 for optimal vegetable production.
Frequently Asked Questions

What is the best soil mix ratio for raised beds?

The best soil for raised beds combines one-third compost, one-third topsoil, and one-third drainage material (perlite, coarse sand, or aged bark). This creates the optimal balance of nutrition, moisture retention, and drainage that raised bed vegetables require. Commercial mixes like Miracle-Gro Organic already provide this ratio, eliminating guesswork for beginners.

How many bags of soil do I need for a 4x8 raised bed?

A 4×8 foot (120×240 cm) raised bed that's 12 inches (30 cm) deep requires 32 cubic feet of soil. You'll need 21-22 bags of 1.5 cubic foot mix or 16 bags of 2 cubic foot mix to fill it completely. Order 10% extra (2-3 additional bags) to account for settling and future top-dressing needs throughout the growing season.

Can I use regular potting soil in raised beds?

Regular potting soil works in raised beds but isn't optimal for vegetable production. Standard potting mixes often lack sufficient drainage for large containers and may not provide adequate nutrition for food crops. Raised bed-specific mixes perform better because they're formulated for the unique drainage and nutrition requirements of contained growing environments.

How deep should soil be in a raised bed?

Most vegetables need 12 inches (30 cm) of quality soil depth minimum, though 18-24 inches (45-60 cm) is ideal for root crops like carrots and potatoes. Shallow beds (6-8 inches/15-20 cm) work for lettuce and herbs but limit your growing options. The deeper the soil, the better the drainage and root development, leading to healthier plants and higher yields.

Should I mix different soil brands together?

Mixing different soil brands can improve performance and reduce costs. Try 70% budget mix with 30% premium blend to get better results than budget alone while staying within moderate pricing. Ensure both mixes have similar pH ranges (6.0-7.0) and avoid mixing peat-based with coconut coir-based formulas as they have different water retention characteristics.
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Tagged with

#raised bed soil#best soil for raised beds#commercial soil mixes#organic potting soil#raised bed gardening#container gardening#vegetable garden soil#garden soil comparison#organic gardening#soil testing
Written By
M

Mike Thompson

Mike's been designing residential landscapes in the Seattle area, with a particular focus on Pacific Northwest natives and sustainable practices. He's a Washington State Master Gardener and worked in construction before landscaping, which gives him a practical edge when it comes to building raised beds and hardscaping projects. He runs a small side business propagating and selling unusual perennials at farmers markets on weekends. His property serves as a testing ground for low-maintenance, wildlife-friendly garden designs. Mike's philosophy: if it requires weekly maintenance, it's not sustainable.

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