Back in 2012, I got excited about a new gardening concept, one which seemed to prove what I had been learning in my own yard — that building soil is the foundation to healthy plants.
The keyhole garden is a self-watering, self-feeding raised bed that is built entirely with recycled materials (stones, brick, phone books, cardboard, newsprint, leaves, manure, grass clippings, etc.) and maintained through the compost center basket. It is essentially a ‘hot compost’ that is directly planted into, volcano shaped for moisture retention in addition to the shading from densely packed and mulched plants on the surface.
Can you say seventy tomatoes in a 6-ft diameter garden? I never would have believed it if I hadn’t heard it myself.
The keyhole was perfected in Africa, where there is very little rainfall, and soil conditions are less than hospitable. The only supplemental watering is through the center compost basket. Aside from kitchen scraps and dishwater (along with other compostables) put there, this garden needs zero supplemental water. ZERO.
It took me more than two years to build a keyhole in my own garden. It never did get planted (life takes over here quite quickly and unexpectedly). In the meantime, this summer, two tomatoes squatted and produced prolifically, so it wasn’t for nothing.
You can see one still bush cherry tomato to the right of the keyhole, growing directly out of the wall. The soil in there must be amazing.
But seventy tomato plants? In one keyhole garden? I might have missed the boat last and this year.
It’s time for me to get serious and get this thing planted already.
Dr. Deb Tolman, Keyhole Expert
If you are a gardener type (I consider myself more of a soil type), then you’ll want to watch this 10-minute interview with Dr. Deb Tolman — our regional expert on the matter — with Central Texas Gardener a few years back. I only just found it; wish I’d seen it earlier.
She quickly dispels the myth that one shouldn’t grow tomatoes in a keyhole, one which I, until just now, fully concurred given the take-over of these sprawlers in my own garden.
She explains the keyhole garden in sufficient detail for the time allotted, in particular these points:
- there is no ‘native soil’ with the keyhole
- the entire 6-ft diameter garden is maintained through the central compost basket
- it is a ‘hot compost’ that is directly planted in
- materials in building the bed invite microbes, earthworms
- soil content is completely broken down in just 4 weeks — HOT!
- moisture retention is due to the volcano design and densely packed planting and mulching
- nothing need be purchased — the keyhole is built with 100% recycled materials
Thank you, Dr. Deb, for lighting my fire once again!
Goodbye, roto-tiller, seasonal bed-prepping,
stooping and picking.
Hello, keyhole — zero-watering, zero-weeding, pest-free
raised bed on steroids!