Build a circular raised bed with a compost basket at the center, then layer soil and plant densely for steady, low-water harvests.
New to the keyhole method? You’re in the right place. This guide shows the full build, the planting layout, and the care routine that keeps the bed productive with modest effort.
The design is simple: a round raised bed with a wedge opening that lets you reach a compost basket in the middle. Food scraps and water go into that basket; nutrients seep out to feed your crops. The result is a compact, accessible plot that sips water yet delivers steady greens and vegetables.
Materials And Sizing That Work
Before you dig, pick a spot with six to eight hours of sun, within hose reach. Aim for a diameter of five to seven feet so you can reach the center without strain. Heights of 24–36 inches suit most gardeners and help drainage on heavy soils.
Here’s a compact bill of materials with plain reasons for each choice and thrifty swaps. Use it while you gather supplies.
| Item | Purpose | Budget-Friendly Substitute |
|---|---|---|
| Stones, bricks, or metal panels | Retain the circular wall | Reclaimed block, broken concrete, pallet wood lined with plastic |
| Wire mesh (½–1 inch) | Center compost basket | Old hardware cloth, a perforated laundry basket |
| Stakes and twine | Mark the circle and wedge path | Scrap sticks and string |
| Cardboard (no tape or glossy ink) | Weed barrier at ground | Thick newspaper layers |
| Brown carbon material | Layering and compost fuel | Dry leaves, straw, shredded paper |
| Green nitrogen material | Layering and compost fuel | Kitchen scraps, fresh grass, manure (aged) |
| Topsoil and finished compost | Growing mix | Quality bagged mix plus homemade compost |
| Mulch | Moisture retention and clean harvest | Straw, leaves, or chipped wood |
| Short piece of pipe or watering tube | Direct water into basket | Perforated PVC or a drilled bottle |
Planting A Keyhole-Style Garden Bed: Step-By-Step
1) Pick The Spot And Mark The Shape
Drive a stake, tie a string half the bed diameter, and trace a circle. Cut a wedge about two feet wide from the edge to the center; this walkway lets you reach the compost basket. Point the wedge north in hot regions.
2) Build The Compost Basket
Roll wire mesh into a cylinder 12–18 inches across and a little taller than the finished bed. Line the inside with straw or leaves. Set the basket at the centerline where the wedge meets the circle.
3) Lay The Foundation
Scalp turf or smother it with soaked cardboard. Overlap pieces by six inches. Add a thin layer of browns, then greens, to start a gentle compost base. This base boosts drainage.
4) Build The Wall
Stack stones, bricks, or panels to your target height, leaving the wedge open as a path. Keep the wall level. In wet climates, add a small spillway on the low side so heavy rain can exit without washing soil away.
5) Create The Growing Mix
Fill the circle like lasagna: four inches of browns, two inches of greens, a thin soil layer; repeat until you reach within eight inches of the top. Finish with a blend that’s two parts topsoil to one part compost. Layers settle; top up later.
6) Set The Watering Tube
Slide a perforated pipe down the basket or tuck a drilled bottle beside it. This delivers deep, even moisture that carries nutrients outward.
7) Plant Densely By Zones
Grow taller or thirstier crops near the outer rim. Tuck quick greens closer to the center, and run compact herbs along the path for easy snipping. Mulch two to three inches deep right after planting.
8) Feed The Basket
Every few days, add a pail of scraps mixed with more dry browns. Keep a loose 3:1 ratio of browns to greens so the basket doesn’t smell and flies stay away. Cap with soil.
Why This Design Works
The central basket drips compost tea into the root zone, which keeps nutrients cycling. The round shape shortens reach distance and adds growing edge. Layering organic matter builds a sponge that holds water yet drains well.
Projects in arid regions report steady yields with modest water, and extension educators teach the same core setup for household plots. Links below explain the concept and its use:
• Illinois Extension explains the compost basket, wedge access, and water-saving benefits. Illinois Extension keyhole gardens.
• A fact sheet from an FAO-linked program shows adoption in Lesotho and the year-round vegetable supply that families reported. FAO fact sheet on keyhole gardens.
Sample Layout For A Six-Foot Bed
Think in rings. Closest to the basket, plant quick cutters that like steady moisture. Around the mid ring, run compact fruiting crops. On the rim, grow taller plants or vines with simple support. Here’s a layout you can copy for spring to summer.
Inner Ring
Looseleaf lettuce, spinach, chives, scallions, basil, and parsley. These harvest fast and keep the soil shaded.
Middle Ring
Bush beans, dwarf tomatoes in cages, peppers, marigolds, and nasturtiums. Flowers draw helpful insects and mark picking spots.
Outer Ring
Cucumbers on a low hoop, pole beans on a tripod, or a sunflower or two for light shade in peak summer.
Care Routine That Saves Time
Watering
Pour water into the basket until the surface is damp a foot away. In hot spells, do that daily. In shoulder seasons, every two to three days is common. A light top-up on the mulch stops crusting.
Feeding
Skip granular fertilizer at first. The slow feed from scraps plus compost in the mix often carries the bed for months. If growth stalls, scratch in a small dose of balanced organic fertilizer around the rim and water it through the basket.
Mulch And Weed Control
Keep two to three inches of mulch at all times. Hand-pull weeds while they’re tiny. That stays easy in a raised circle since the soil stays loose.
Pruning And Training
Pinch basil often, tie tomatoes to their cages, and guide cucumber tendrils onto the support. Trim anything that shades the inner ring too much.
Troubleshooting: Quick Fixes
Bed Settles Too Much
Top up with compost and soil. Add more browns to the basket and water well to restart activity.
Smelly Compost Basket
Add two buckets of dry browns for each bucket of food scraps, and cap with soil. Keep meat, dairy, and oily foods out.
Dry Spots Near The Rim
Water the basket, then give a slow soak on the rim. Add mulch where you see bare patches.
Slugs Or Snails
Use copper tape on the wall or set shallow beer traps near the wedge path. Harvest at dusk with tongs.
Ants In The Basket
They moved in because it’s too dry. Soak the basket, add fresh greens, and keep the ratio skewed toward browns afterward.
Seasonal Planting Plan For A Six-Foot Keyhole Bed
Use this compact planner to rotate crops and keep harvests coming. Swap in local favorites.
| Crop Group | Spacing & Count | Notes |
|---|---|---|
| Leafy greens | 6–8 inches; 20–30 plants | Cut-and-come-again harvests near the basket |
| Tomatoes (dwarf) | 2–3 cages on the mid ring | Choose determinate types for tidy growth |
| Peppers | 12–18 inches; 3–4 plants | Mulch well to keep soil warm |
| Beans | Bush: 6 inches; Pole: 3–4 vines | Use a tripod or low trellis |
| Cucumbers | 2–3 vines on rim | Train up to save space |
| Herbs | Clumps by the path | Chives, parsley, basil, dill |
| Root crops | Radish and beet in gaps | Sow between larger plants |
Step-By-Step Planting In One Afternoon
Morning: Hardscape And Layers
Gather wall pieces, mesh, and cardboard. Mark the circle, set the basket, build the wall, and lay the first layers. Soak the layers well.
Midday: Soil Blend And Mulch
Blend soil and compost, fill to near the top, then spread mulch. Insert labels and supports now; that’s easier than later.
Afternoon: Plant And Water
Set transplants by rings, sow quick seeds in the gaps, water through the basket until soil is damp a foot out, and finish with a gentle spray over the mulch.
Safe Scraps For The Basket
Good: fruit and veggie trimmings, coffee grounds with paper filters, tea leaves, crushed eggshells, stale bread, spent flowers, clean cardboard bits.
Skip: bones, meat, fish, oils, pet waste, glossy paper, big citrus loads, or plant matter treated with persistent herbicides.
Keep the basket damp like a wrung sponge. If insects swarm, add a thick cap of browns and soil and pause fresh scraps for a week or two.
What To Expect Over The First Season
Week 1–2: Layers settle. Keep the basket damp. Greens root fast; herbs perk up. Add soil if the surface dips.
Week 3–6: Plants knit together. You’ll harvest lettuce and herbs. Start light pruning and weekly scrap additions.
Week 7–12: Fruiting crops set flowers. Keep mulch deep. Train vines and feed the basket more often in hot spells.
Week 13+: Harvests ramp up. Add finished compost to holes left by pulled plants and keep rotating quick crops into those gaps.
If you like more structure tips for raised beds, this Texas A&M guide shows wall builds, soil mixes, and irrigation sketches that transfer well to a round setup. Raised bed construction guide.
Ready to get growing? Snap a photo of your setup, label the rings, and start feeding the basket. The small daily habit of scraps plus water is what powers this style long term. Keep notes on planting dates and yields for better planning next season.