hey mike - great topic! I've been considering keyhole design for an herb garden.

never heard of a square one - I thin the round design is meant to maximize growing around the the center hole, and it can only go out so far from it.

However, you could cheat and add water/fert tot he corners, but then it kind of defeats the purpose...

Interested to see what anyone else has to say!

I think the basic design of keyhole gardens is so cool. I have plans to build one when we redo our lowest hillside bed. Built into the slope, it will bulge out and have a walk-in nook. I'm planning to save some of this year's cornstalks for the structuring the compost column. Might be fun.

Here is a link that might be useful: keyhole garden plan for Texas

T bird,

I think you are right that the circular design would be more efficient at distributing the moisture and nutrients from the compost, but I think a square may work well also as long as it isn't too large, and the compost area is sized right. I really wonder how well the nutrients do leach in the traditional design. I would love to see some real world success stories. I have found a lot of info on new builds and what not, but not a lot of stories or "through the season" type progressive info showing how well one actually performed for someone.

Hopefully well get some people on here with some good examples to share.

keyhole only an adaption of raised bed gardening, mainly for confined are so the gardener can reach all parts of the garden, in that sense a garden should not be wider than 1 meter or 4' about, that is a consideration that needs to be made so circular would need to be less than 2 meters across.

the idea not to cause compaction by walking on the garden.

so nothing magical in keyhole. for me keep it simple.

len

Here is a link that might be useful: lens straw bale garden

The only thing that bothers me about traditional keyhole building (permaculture style) is that most home gardeners would benefit a lot more by taking the compost created for such a large amount of soil space and distributing it to other "regular" gardens.

If you have an excess of compostable materials it's a good way to get rid of it, but they system itself works on very high compostable additions for soil structure, nutrient, and water retention qualities.

It's basically growing stuff in an aerated no-turn compost pile...well, not that simple, but that's essentially what's going on.

Never heard of it before so had to look up what it is. Seems to be, from what I read, a predominately UK/European approach to gardening.

But as Len said (and has posted pics) sheet compost gardens - a similar approach - are a fairly common practice.

I guess my main question would be, what are the benefits, the appeal? Other than the benefits of compost of course which can benefit any garden size or shape?

The quality of the compost used or made, the diversity of its ingredients, would determine the quality of the garden and far too many simply don't understand the underlying principles of composting.

Dave

Dig, the appeal to me would be the not having to water(or at least very reduced watering) or fertilize, due to the centrally located compost pile. I think however that a vermicomposting approach would probably work better in a setup like that rather than traditional hot pile composting. I think if you incorporated the worms in to the mix, they might help to distribute the nutriients in the compost out t the surrounding garden. Though, proper composting worms dont burrow too deep from my understanding, so maybe that would not be the case. Also, it may be difficult to overwinter the worms, adding to the challenge.

T bird, I think you are right that hilling the compost area and sloping down to the edge of the garden would probably be the best approach.

Nc, I agree that most home gardeners would benefit more from creating a separate compost pile and using it in their traditional gardens. Which is what I currently do. However, I love to experiment, and finding enough stuff to compost is definetly not an issue.

I would just really love to see a true success or failure story before trying to give it a go.

I can't comment on keyhole gardens, but something else that might appeal to arid climate gardeners is the wicking worm bed. I use a variation of this with small planters made from foam broccoli boxes from the produce market and several large (75L tubs). The link below gives a fair bit of information and pics from someone who does it on a larger scale than I do, in an even hotter and more arid climate.

Here is a link that might be useful: some info on wicking worm beds

Before I ever heard of keyhole gardens, I had started using a similar system to grow peppers. I planted three peppers around the outside of one of the small 2 ring tomato cages(for support) and used the center as a pit compost that grew into a pile. I'd sprinkle a little organic fertilizer in there from time to time and pile on pulled weeds from nearby beds. It works great for peppers, might host slugs in a cool-season situation.

Better late than never... keyhole design is intended to maximize the useable garden space. Filling the middle with compost defeats that purpose. Keyholes are a key feature (no pun intended) in permaculture systems where the design maximizes the use of "edges" (which might be described as transitional zones that promote diversity). The following link provides some "how to design" advice, but for a real understanding of the functions, read "Gaia's Garden: A Guide to Homescale Permaculture".

Here is a link that might be useful: Ecological Garden

i don't need the mythology of permaculture, i support you do in you yard what best fits, for me circles can take up space as most yards are rectangles/squares, with key hole you can build a large squarish garden with cut in designed so that you can reach to the centre of the garden by hand, i have space so i use rectangle garden 1 meter to 4' wide, the length no more than about 6 meters.

looked at that gaia link, can see waste of space they would be better for most if like a square 'U'.

len

Here is a link that might be useful: lens garden page

OK - so I did a search on keyhole gardening. I found this claim twice:

"The sustainable gardening method was developed by a humanitarian aid organization in southern Africa, where resources are scarce and the climate unforgiving. There, three keyhole gardens can feed a family of 10 all year long, reports the BBC."

Three six foot diameter gardens - with the compost core and 'key' slot subtracted - can feed a family of ten all year long? What in tarnation are they growing? Stop and think about that claim. Two adults and eight kids - or three and seven - are being fed from LESS than three 4x8 foot plots? Excuse me if I'm not buying that claim.

I really don't see the virtue of this system. You need the stone to make the wall, and the compost bin and key slot rob you of space. Why would you put the compost bin within the garden, when you can put it somewhere that's waste space - like in the shade? And of course, since you can't turn the pile, it will break down slowly. And any nutrients that come out of the pile will not be spread evenly. Rain is going to carry nutrients down through the bed to the bottom, whereas many of the roots are very close to the surface.

I have no doubt you can grow in such a raised bed, but I can't see how this system is better than a normal raised bed. And of course, if space is tight, this actually wastes it. In my yard, I'm sun-limited due to neighbor's trees and my house. I need to use every inch of sunlight, and this would be wasting it.

If you have an open yard with unlimited light, and you have the urge to build stone walls, then have at it.

There's a (not major) battle in permaculture going on with self-sustaining, low labor setups/practices vs. using resources more wisely by separating some of those inputs and moving them, when needed, to areas where it would be of benefit.

I'm a certified permaculturalist and while I butt heads with some of my peers who are purists, I have many on my side (that have pushed this idea before me) on separating some of the self-feeding design aspects in order to use materials more effectively in the short-run. In some design systems it's easier for some of us to want to add more labor for short-term benefits which are not destructive to the long-term goals.

Btw, getting certified isn't hard...it's a theory/practice + design 2-part process that isn't tightly regulated.

There's a lot to learn from permaculture, but we can't forget that one of the most important parts is learning from the design process to better use available inputs. This may go against the theoretical grain in some instances adding more labor to the process at the expense of the self-feeding parts of the process.

I just took a look on Youtube. The idea comes from Africa, and Lesotho in particular. In Lesotho, a lot of the people live on mountainsides. This is, of course, not a great place to start a garden. A raised bed garden with easily available stone walls makes sense - you don't have much soil in the first place, so you keep it contained. And round walls make sense, because it's easier to build a round wall than a square one - the corners are trouble. So that sort of general structure is a good idea for that particular environment. Outside of the general raised bed concept, I don't see how it transfers especially well to a temperate, rainfall climate on level ground.

By the way, regarding the claim from my earlier comment that three of these gardens would feed a family to ten: The girl in the video I watched showed three pots with their basic foods in them. One of them was pumpkin, which they obviously aren't growing in six foot diameter raised beds.