What is Mel's Mix and why is it standard for Square Foot Gardening?

Mel's Mix consists of exactly 1/3 coarse horticultural vermiculite (for moisture and nutrient retention), 1/3 peat moss or coconut coir (for aeration and acidity balance), and 1/3 blended compost (from at least 5 different sources for rich nutrition). It never compacts and never requires tilling.

How many plants fit in one square foot?

SFG divides crops into 4 standard rules: Extra large (1 per square: cabbage, broccoli, peppers, determinate tomatoes); Medium (4 per square: lettuce, Swiss chard); Small (9 per square: bush beans, spinach, beets); Extra small (16 per square: carrots, radishes, green onions).

How deep should a raised bed be for vegetables?

A standard depth of 6 to 8 inches (15–20 cm) is sufficient for nearly all vegetables in Square Foot Gardening because Mel's Mix is light and friable, allowing roots to spread easily. Root crops like long carrots benefit from 10–12 inches.

How do I calculate cubic yards of soil for a raised bed?

Multiply Length (ft) × Width (ft) × Depth (ft) to get total cubic feet, then divide by 27. For example, a 4x8 ft bed with a depth of 1 ft (12 in) = 32 cu ft / 27 = 1.19 cubic yards.

Can coconut coir replace peat moss in Mel's Mix?

Yes. Coconut coir is an environmentally sustainable alternative to peat moss. It offers a near-neutral pH (5.8–6.8) and rewets more easily than dehydrated peat moss.

DIY & Trades

Square Foot Gardening Plant Spacing & Raised Bed Soil Calculator

Name: Square Foot Gardening Plant Spacing & Raised Bed Soil Calculator
Author: AnshuTechy

Plan high-yield raised garden beds with Mel Bartholomew's Square Foot Gardening (SFG) grid matrix, companion planting spacing charts, and Mel's Mix 3-part soil volume calculator.Documentation & FAQs ↓

Square Foot Gardening Plant Spacing & Raised Bed Soil Calculator — Interactive Console

Runs locally in your browser • Instant output

Bed Length (ft)

Bed Width (ft)

Depth (Inches)

Click Crop & Paint On Grid

4′ × 4′ Raised Bed Grid106 Plants | ~95 lbs Harvest

Synergistic planting harmony active! (10 companion bonuses)

Mel's Mix Soil Recipe Breakdown10.7 Cu Ft (0.40 Cu Yd)

1/3 Coarse Vermiculite3.6 cu ft(~1 bags of 4 cu ft)

1/3 Peat Moss / Coir3.6 cu ft(~1 bales of 3.8 cu ft)

1/3 Blended Compost3.6 cu ft(~4 bags of 1 cu ft)

Step-by-Step Instructions

4 Steps to Completion

1Phase 1

Enter the dimensions of your raised bed (length, width, and depth in feet or inches).

2Phase 2

Review the required total soil volume in cubic feet, cubic yards, and commercial bag quantities.

3Phase 3

Inspect the 1/3 vermiculite, 1/3 peat moss/coir, and 1/3 blended compost recipe breakdown.

4Phase 4

Use the interactive plant spacing selector to populate each 1x1 ft grid square with optimal crop densities.

Practical Use Cases & Real-World Scenarios

Urban Backyard Raised Bed Planning

Design 4x4 or 4x8-foot raised beds to maximize fresh vegetable yields in compact suburban and urban garden spaces.

Spring Soil Shopping & Nursery Bulk Orders

Determine exactly how many bags of compost, peat moss, and vermiculite to purchase at the garden center to fill new timber beds.

School & Community Garden Education

Teach beginner gardeners and students how intensive grid spacing eliminates weeding and conserves water compared to row planting.

Related Editorial Guide on AnshuTechy10 Best Gardening Apps for Every Gardener in 2026

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100% free, private in-browser utility with zero server uploads.

Square Foot Gardening Plant Spacing & Raised Bed Soil Calculator

Step-by-Step Instructions

Practical Use Cases & Real-World Scenarios

Interactive 1x1 Foot SFG Grid Matrix

Mel's Mix 3-Part Soil Volume Recipe

Raised Bed Dimensional Math & Bag Counts

Companion Planting & Sun Exposure Insights

Frequently Asked Questions

10 Best Gardening Apps for Every Gardener in 2026

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