Raised Bed Planner: How to Design, Build, and Plant a Raised Bed Garden
The right bed, the right soil, the right layout. Plan a productive raised bed from scratch.
Raised beds are the most reliable way to grow vegetables. You control the soil from day one, drainage is built in, weeds are minimal, and you can start on any surface. But a raised bed is only as good as its design. The wrong dimensions waste space. The wrong soil mix stunts roots. The wrong crop layout creates shade problems.
All spacing data and companion relationships come from the Plant Anywhere garden planner with 216 crop profiles.
Choosing the Right Bed Size
Width: 3 to 4 feet
You need to reach the center from either side without stepping in. 4 feet is the maximum for most adults. Against a wall, limit to 2 to 3 feet.
Length: as needed
Most common: 4 feet (square foot gardening), 6 feet, or 8 feet. Standard lumber comes in 8-foot boards, minimizing waste.
Depth: 10 to 18 inches
6 inches for herbs. 10-12 inches for most vegetables. 18 inches for root crops or beds on hard surfaces.
How Much Soil You Need
| Bed Size (L x W x D) | Volume (cu ft) | Volume (cu yd) | Bags (2 cu ft) |
|---|---|---|---|
| 4x4x10in | 13.3 | 0.5 | 7 |
| 4x4x12in | 16 | 0.6 | 8 |
| 4x8x10in | 26.7 | 1.0 | 14 |
| 4x8x12in | 32 | 1.2 | 16 |
| 4x8x18in | 48 | 1.8 | 24 |
| 3x6x12in | 18 | 0.7 | 9 |
Buying soil in bulk by the cubic yard is 50 to 70 percent cheaper than bags.
Building Materials
Cedar lasts 10 to 15 years, naturally rot and insect resistant. Redwood equally durable but pricier. Douglas fir lasts 5 to 8 years. Pine cheapest but rots in 3 to 5 years. Avoid pressure-treated lumber for food gardens. Galvanized steel lasts 20+ years. Concrete blocks are affordable masonry option.
The Right Soil Mix
Standard formula: 40 percent topsoil, 40 percent compost, 20 percent perlite or coarse vermiculite. Do not use garden soil alone (compacts, weed seeds, pathogens). Do not use straight compost (settles 30 to 40 percent, too nutrient-rich). Top-dress with 1 to 2 inches of compost each spring.
Planning Your Crop Layout
Place tall crops (tomatoes, pole beans) on the north end. Medium crops (peppers, basil) in the center. Low-growing crops (lettuce, radishes) on the south end.
Companion planting in raised beds
Tomato + basil (repels aphids). Lettuce + tall crops (afternoon shade). Carrots + onions (repels carrot fly). Avoid tomatoes near brassicas, beans near alliums.
The Plant Anywhere garden planner draws companion and antagonist lines between crops as you drag them onto the raised bed layout, tracking 248 companion relationships from the companion planting database.
Example: 4x8 bed summer layout
- North end: 2 tomato plants (24-inch spacing), caged
- Row 2: 4 pepper plants (18-inch spacing)
- Row 3: 8 basil plants (12-inch spacing)
- Row 4: Bush beans (4-inch spacing), 20 plants
- South end: Lettuce succession (6-inch spacing), replant every 3 weeks
Design Your Raised Bed with Plant Anywhere
Design your raised bed layout -- free
Related Guides
- How to Start a Vegetable Garden: Beginner Guide 2026
- Seed Starting Schedule 2026: When to Start Seeds Indoors by Zone
- Frost Dates Guide: How Frost Dates Work and How to Use Them
- Indoor Herb Garden: Growing Herbs Year-Round
- Raised Bed Planner: Design Your Perfect Layout
- Watering Guide: How Much Water Does Your Garden Need?
- Browse All 216 Crop Profiles
- Find Your Frost Dates by ZIP Code
Frequently Asked Questions
Best size for a raised bed?
4x8 feet is most popular: 32 sq ft, fits 8-10 crops. 4-foot width lets you reach the center from either side.
How deep should a raised bed be?
10-12 inches for most vegetables. 18 inches for root crops. 6 inches for herbs and greens.
Best soil mix for raised beds?
40 percent topsoil, 40 percent compost, 20 percent perlite or vermiculite.
What wood for raised beds?
Untreated cedar is best (10-15 years). Avoid pressure-treated lumber for food gardens.
How much soil for a raised bed?
Length x width x depth in feet = cubic feet. A 4x8x1 bed needs 32 cu ft or about 1.2 cubic yards.