The Incredible Productivity of the Keyhole Garden
I get almost 5 pounds of food per square foot from this simple, organic, and sustainable garden
Keyhole Garden in May 2022
My keyhole garden turned three years old a few weeks ago and it continues to amaze.
Aside from a few days halfway through its first year, it’s been in non-stop production the entire time. Baking heat, freezes, pouring rain, wind, it doesn’t matter, nothing stops this thing.
Right now the early spring crops – leaf lettuce, broccoli, carrots, peas, red and brown onions, dill, and parsley – are giving way to early summer crops – tomatoes, bunching onions, summer squash, basil and cilantro. It’s basically a whole food garden packed into one 8 foot circular bed.
If you’re not familiar with the keyhole garden concept, it’s a circular raised bed with a composting bin at the center. A notch, like a keyhole, is cut into the side of the bed to allow access to the compost bin. The bed’s height and shape provide good drainage and easy access from any angle, while the compost bin leaches nutrients back into the bed keeping the plants in it happy and well-fed.
Another advantage of the keyhole garden is one I wasn’t aware of when I first built it. It turns out the compost bin’s activity acts like a little organic radiator keeping the soil surrounding it quite warm even when the weather’s cold and ugly for an extended period.
A peek in the Keyhole Garden Compost Bin
In the late fall the plants’ roots dig into the warm soil and continue producing for a much longer time than would otherwise be possible. In my case, where it freezes overnight often enough but doesn’t snow, I’ve had bell peppers, tomatoes and basil growing alongside broccoli, carrots and onions all winter (I don’t even cover them).
In April of last year I estimated we harvested about 150 pounds of fresh herbs and vegetables a year in the first two years – roughly 1-½ pounds of food per square foot of keyhole garden.
Not too bad.
Later that spring I mastered a few tricks for “pie slice”, “high-low”, and succession planting (more on those later) that allowed the garden to more than triple its output, so we’re getting close to 4-½ pounds of fresh food per square foot. Oh, and all with no additional fertilizer or soil beyond what the compost bin provides.
Now that’s great!
Add in that it helps us reduce our food and green waste to near zero, and my total investment was less than $200, and you’ll understand why I think the keyhole garden is incredible.
If you’re considering your own garden and you want something that’s inexpensive, organic and sustainable, you definitely need to give the keyhole garden a try.
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I’m going to try the keyhole garden as soon as I can get the materials, this summer. My problem will be winters. I do not live in a near-perfect climate. It would be nice to have fresh veggies in the winter, however in my Zone 4b/5a where winters can get down to -20 for a week at a time, that’s only possible if you grow them in the basement under lights. However, such a great little garden would be nice the other 8 months of the year.
And on 6.5 acres, there’s plenty of room around here.
Question..you said 5 lbs per sq ft. What is the harvest consistency like? Do you harvest and eat from it every day? Do you think it will grow enough for 2 people to eat from it on a daily basis, with some supplement from the grocery store for meat and fruit? Or would I need 2 gardens for variety and constant supply of salad fixings?
This type of garden will definitely extend the growing season — as much as 6 weeks on either end if you’ve got at least 5 hours of sunlight. If you make one from stone or brick rather than wood, you may be able to get even more since since stone is a good insulator and will hold the heat longer.
I don’t think you need two gardens. One will generate a lot of food if you’re smart about it. After 3 years I’ve got my garden dialed in to the point where I can do continuous succession planting — every two weeks or so — so we can eat from the garden daily. As one crop peters out, there’s another right behind it ready to take over. Not just lettuces and leafy greens, but cucumbers, peppers, squash, corn, beans, tomatoes, and herbs like basil, cilantro, dill and parsley. It really is our kitchen garden.
Last year, we challenged ourselves to be a food sufficient as possible. We still bought meat and dairy, and some dried staples, but between the keyhole garden, our “main” which has long season staples like dried beans and corn, and the citrus, berries and stone fruit in the orchard, we spent a mere $11 on fruit and vegetables for all of 2021.
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