Keyhole Raised Beds

David Trammel's picture

Interesting shape for a raised bed.

Why You Should Consider Building a Keyhole Garden

"Anybody who’s ever grown vegetables in a raised bed garden knows how awesome they are at producing an incredible yield that eclipses that of a traditional garden. But no matter how productive your design has been, chances are that it’s not as productive as the one I’m about to share with you. What’s it called? A keyhole garden. Intrigued? Read on.

A keyhole garden is round, roughly six feet across and has waist-high walls. The name comes from the distinctive shape of the garden, which has a round column in the center and a slot jutting out on one side, making it resemble a keyhole. As much as I’d love to say I came up with this method of raised-bed gardening, it is believed to have originated in areas of Africa in which communities had very poor soil and a long dry season and, as such, were seeking a means of growing fresh veggies as economically as they could."


I like how its waist high, good for someone like me that's older and has trouble bending. I'm guessing that the wire cylinder in the center is a composting pile.

The circular design does waste some floor space but there are square designs too. Might be a way to camouflage your composting piles in a urban setting too, where neighbors might gripe about any imagined smells.

ClareBroommaker's picture

When I first started my backyard double dug, intensively planted raised beds, it was sort of a keyhole rectangular design. My point was to use as much available space as possible in a narrow (25 ft) space, and to have good access to tend to the beds. I did not put the compost heap at the center, but moved it every few years. The beds were only raised something like 10-12 inches. Sometimes they were unbordered, sometimes they had scavenged boards securing them.

I did not bring in other soil from outside the garden but used what was there. We have really deep, nicely textured nearly rockless soil with a great balance of clay, silt, and sand. My main tasks were to fluff up the soil, bring up nutrients from deep below, and add humus and nutrients via compost, mulch, and occasional buried fish guts and bones.

The paths (except the pre-existing concrete one) were dug down a little in order to add soil to the raised bed. The paths were just wide enough to have space to squat between the beds. Sometimes the paths were mulched with wood chips. Sometimes I just let whatever wanted to grow there do so.

Here is the plan. This represents half the backyard garden now. More plantings continued over the years in the direction opposite the grape arbor. The unsketched portion looks more like an ornamental garden, but includes more cooking herbs, shrubs, alliums, spots to tuck in chiles, figs, gooseberries, and formerly quite a few roses (lost forever to rose rosette disease.)

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alice's picture

Dry stone walls, which is what that method of construction is called over here, might not work for the UK's mild damp climate. It does say it was developed in areas with a long dry season which is exactly what we don't have over here. I suspect I would end up with an enormous slug population if I built with un-mortared stones like this. I think mortared or rendered masonry would be better for our climate, as it would provide fewer slug hideyholes. But I have noticed that rich people here who like to grow veg do seem to build these waist high beds, I've mainly seen brick, and I am sure that makes gardening very convenient.

mountainmoma's picture

The original keyhole garden concepts I have seen and was taught had no walls. The concept is to minimize space lost to paths, so to maximize growing area to path ratio.

you have a main path, then little paths were you get into the larger growing area, these little paths, the keyholes, are as close together as needed to reach all area of the growing area from at least one of the keyholes, so some people are more comfortable with different degrees of reach. In practice, they are not necessarily round in the center, the shape there is more organic by how large the person is working, etc... usually there is not some large round space as the whole point is to minimize path space to growing area

As far as the example in the link, ,ost of us would absolutely not put a compost heap there. For many reasons, first it gets in the way of being able to reach a large porion of the growing area,it is in the way. Second, it is not as wide as is recommended, so it may not heat up as much as it should. Third, the acess to the compost is so limited, it would be a pain to get the finish compost out and move it. And, if the point is to not move the compost but to let the nutrients leach into the bed, it would work better to not compost at all and just tuck the organic matter, kitchen scraps, into the soil or under the mulch directly in the planting area ( unless you have rats)

Tude's picture

I actually built one of these in my garden as an experiment. Unfortunately I used dry stones and didn't have the best stones, so the walls are kind of falling down, but the bed itself is really nice, and I love having the compost basket in the middle. For me it really just worked as a short (maybe a foot high) raised bed in the beginning, but it will be interesting to see how well it works this year now that the basket is full of compost and loads of worms.

I'm going to try to attach a picture here if possible of it last summer while I was experimenting with what to plant in it. I have just about every form of raised bed and non raised bed in my backyard, which I use for my "testbed" preparing for when I have some actual property some day (fingers crossed!)

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Tude's picture

Here is another picture from a different angle

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