Interesting keyhole/hugelkultur design

I came across this in our electric co-op's newsletter. The designer doesn't mention anything about permaculture/hugel/etc. but uses many similar ideas to make a pretty interesting little ecosystem. She says this performs very well in our current drought. Click here for the article and here for the designer's site with a pdf.

While I'm not crazy about the cemented rock wall around the outside, I think this is a pretty cool implementation of multiple practices all boxed up together in a small, productive unit. She also does it in old boats, various kinds of containers.

It's cute! If you used stacked rocks, no mortar, it could provide plenty of habitat for lizards, snakes, toads and frogs.

Tyler--very true. I would be concerned about them falling, although if you build it well it should be pretty sturdy, especially with a curved shape for support. I also thought about using logs. You could angle every few logs at a 90 degree angle to the wall so they jut into the bed and provide support. This might help increase water storage too. Downside of course would be it would eventually rot.

I was very surprised to find this video: http://www.youtube.com/watch?v=ykCXfjzfaco The above article and pictures are a souped up version of the African keyhole beds in the video. I'm surprised because I was trying to think of ways to improve upon Hemenway's keyhole beds to make them more drought tolerant a year ago and I never came across these!

Really excellent video showing the steps. Thanks. Hugelkultur beds usually make use of logs, but I don't think they have access to logs, so they use a layers of brush instead. The central tower is filled with compostable material, so the composter and the bed are built together. This makes sense, but I wonder if actually works. I don't see how the compost would radiate out towards the edge of the beds, unless you were growing perennials with deep root systems so they could go to the nutrient source. Would it work?

Earthworms will move materials around within the bed, I think. And many annuals have quite large root systems.

Todd -- I wonder too if that works, or how well it works. I'm inclined to believe it works great because of the origin--I don't think Africans in poverty would waste materials and time on things they didn't know to work, but this might not be accurate thinking. (a note after writing that: not meaning to assume that Africans or even those in the video are automatically in poverty. The video comes from a charity organization that teaches people in poverty to grow a garden with materials they have, hence my connection.)

I believe this deserves a trial

Chris Dean wrote:Todd -- I wonder too if that works, or how well it works. I'm inclined to believe it works great because of the origin--I don't think Africans in poverty would waste materials and time on things they didn't know to work, but this might not be accurate thinking. (a note after writing that: not meaning to assume that Africans or even those in the video are automatically in poverty. The video comes from a charity organization that teaches people in poverty to grow a garden with materials they have, hence my connection.)

I believe this deserves a trial

Totally agree it needs a trial. I was just trying to think it through. It could work simply because the original materials act much like a standard hugelkultur. The idea of the central tower flowing into the circle is brilliant. Again, just not sure how it could work. Though as Tyler says, it maybe worms or mushrooms or something. Most of the annuals I grow, except maybe tomatoes, don't seem to have root systems that long. Maybe they have a longer growing season so there's more time for root growth?

i'm reminded of an old Organic Gardening magazine design my dad did years ago. it involved a wire compost bin in the center of a garden bed with plants surrounding it. the outside bed wasn't built up as much though. this was maybe 25 yrs ago
to irrigate, water was dumped into the center, flushing the nutrients to the outside. it grew great tomatoes. the roots found their way inside, they were trellised around and over top of the cage

Going to try one out this year. I built this out of stone and cob (pretty rough cob--it wasn't "perfectly" mixed), the bottom is filled with logs for hugelkulture, with some broken down newspaper and such here and there. I ran a soaker hose under the top layer and planted some cover crop that hasn't come up yet. Looking forward to growing in it!!

Wouldn't the compost "basket" soon clog up, plus there would minimal airflow, right?

Roman Milford wrote:Wouldn't the compost "basket" soon clog up, plus there would minimal airflow, right?

i think it becomes more of a 'feeder' for worms and soil critters , not like an aerobic hot compost pile. looks like a natural version of the in-bed "worm towers" made of pvc pipe/5gal buckets.

this seems to me like a really innovative way to work hugelkultur into lanscaping so that the raised beds actually add aesthetic property value, this would make people more willing to have hugelkultur beds in their backyards and such in suburban areas

for beds not within immediate range of the house, one could replace the compost tube with a stump innoculated with mushroom spores to add edible mushrooms to the bed, it might also make a good asparagus bed eh?

@Devon

I've never tried anything with mushrooms, only read a very little bit. Would the lack of oxygen be a problem?

well i have not yet grown any shrooms myself though i have heard others suggest burying a stump halway like a post in a hugelkultur bed, i also think it would work well with shrooms that naturally occur on stumps, such as chicken of the woods, the top of the stump would be exposed and the bottom would be buried within the bed, making it look similar to the pictures above, just a half-buried stump replacing the compost bin

short answer, i think it depends on mushroom variety but i would say, generally speaking, no.

I'm looking at providing access to deeper into my hugelkultur by similar means. I am lining the perimeter of a three-foot deep trench with warehouse pallets standing on end, where I will close off the channels where the forks go with plugs that I will build for the purpose. I am taking two trees out in the back yard, as well as raising the canopy of an old Elm we have in the north west corner of the yard. Half of the wood I will have chipped. A quarter I will mix into the bed, a quarter will make great mulch for my walkways and raspberries, and I will store the rest in containers by the bed for carbon contributions atop garden waste that will go into the plugged channels on the bed's perimeter. Eventually, the channels will all be filled, and the pallets will rot away, but by that time the perennial food shrubs and cane berries and maybe dwarf fruit trees will replace their structure with a thick root mat. I hadn't thought of making it in the shape of the keyhole bed, though. I will play with that idea. That and innoculating my hugelkultur bed with some compatible mushroom strain. Any thoughts?

-CK

also, chris dean, hows your beds coming, anything growing up and out yet?

The ground's still largely frozen where I am, and I have as yet to dig the hole the bed is going in to, half the wood going into the bed is still standing, but I have the bulk of the pallets needed, I think I will use one course in the hole and another course set in a foot or so. If the tiers work, I'll have one sub-surface and at least two to the top of the bed, maybe three. I've also been thinking of structuring the green elements of the bed such that they would provide support for a kneeling space around the top of the bed's perimeter. I was also thinking of using the course of pallets buried around the perimeter of the trench as insulated panels, filling the void space with paper waste from the print shop I work in, and sealing each individual pallet with a garbage bag. I have a feeling this would act as insulation from the ground freezing, lengthening the bed's growing season.

-CK

Devon Olsen wrote:also, chris dean, hows your beds coming, anything growing up and out yet?

I'm gone from home for a week and got someone to do some occasional watering, but when I left there were sprouts from the cover crop coming up. Will get some pictures up of it when I get back!

A couple of weeks after planting the green manure (oats, field pea, hairy vetch). I know it's pretty early to say much about the bed yet, just wanted to show some green:) I haven't watered this bed yet except a sprinkling when I planted them, but we've gotten about 1.5 inches of rain in the last 2 weeks. Planning on this being a tomato bed this year.

VERY nice update man, thanks!
it does look pretty good with some green though i still feel(not sure if i mentioned this before) that it may look better if there wasn't dirt/cob(if thats what that is) showing between the rock, if i were designing it for someone else or for a place that i may sell down the road i would probably avoid that myself, but its still works just as good i woud assume...

Devon Olsen wrote:it may look better if there wasn't dirt/cob(if thats what that is) showing between the rock

That's surprising! My wife and I love the look of cob, and I actually got hired to build a taller bed made of rock and cob for someone who saw this pic! A good thing about the cob instead of cement is it will be cooler in the summer.

To each his own

interesting indeed!
i definately wouldn't put cememnt between the rocks or anything... and it could be that cob looks better than simply stacking the rocks when in person
i do think that the cob would look amazing if your were near a pine forest or anything, if you were trying to give a straight natural look, i was thinking that in most suburban yards it may look better without the cob though, as cleaner looks prevail in these environments imo
i am building one of these this summer with a large stump in the middle... we'll see what i decide to do with it:)

Looks good, Chris. Are those homemade "ollas" in the background?

Devon Olsen wrote:interesting indeed!
i definately wouldn't put cememnt between the rocks or anything... and it could be that cob looks better than simply stacking the rocks when in person
i do think that the cob would look amazing if your were near a pine forest or anything, if you were trying to give a straight natural look, i was thinking that in most suburban yards it may look better without the cob though, as cleaner looks prevail in these environments imo
i am building one of these this summer with a large stump in the middle... we'll see what i decide to do with it:)

Good point--and the person who is hiring me lives out in the country:) I have seen these built without any kind of mortar at all though, just the rocks or bricks stacked. Any kind of masonry bricks would look good in a suburban setting, and you could put them up in no time.

@Tyler--Ollas indeed! I made them last year but didn't get them in the ground, so this year I will hopefully get them in and experiment with them. I procrastinate because of the holes that need to be dug:) Have you had any experience with them?

I was going to make some but didn't get around to it, so, no I don't have any experiences (yet)

what are ollas?
and yes digging, sucks:(

Neato thread... thanks for the original link and subsequent pics...

If rocks are a pain to source, standard landscaping bricks (that overlap the back of each row below) would be very sturdy and seemingly perfect for something like this.

Good idea, Matt. I was thinking about doing something similar, as the hugelkultur I want to put in as soon as the ground is thawed requires me to dismantle an existing retaining wall. I am going to try to find such blocks out of landscapers' waste, but there I was thinking that if I couldn't find any, that I would likely just price the cost of stone from the quarry, specifically any stuff (cheapest possible, or ends) used for dry-fit installations. I don't have to worry about an HOA breathing down my neck, but I figure anyone who does can use that stuff. I last worked with some that I think was green slate (really pricey landscaping job where I was facing and dry-fitting a decorative face to a cinder-block raised bed and set of stairs set on the house foundation; not my design ). I'd go as cheap as possible, but if the wall was tied into the bed with brick ties or built so it corbels (I think that's the word) back row on top of row 1/8" to 1/4" depending on bed height, you could likely use tumbled pavers (much cheaper) or brick you salvage yourself, though depending on where it comes from, I would be wary of toxicity. I like the idea of using masonry to side the beds, as they should hold more heat longer than just dirt alone, and prevent unwanted erosion.

For sure.

I'm using those concrete landscaping blocks to create a low bed all around my house, and they end up with lots of little spaces and gaps... nice for little niches of "rock gardening" plants and for little critters to get in and out.

Ollas are unglazed clay pots which are sunk into a planting bed and then filled with water to efficiently irrigate with little evaporation.

Devon Olsen wrote:what are ollas?
and yes digging, sucks:(

Check out this link to see diy ollas that you don't have to dig such a deep hole for!

could we replace the centre with bamboo (pushed thru w pipe etc) or a PVC pipe w holes or drainage pipe w holes?

amarlover Hatfield wrote:could we replace the centre with bamboo (pushed thru w pipe etc) or a PVC pipe w holes or drainage pipe w holes?

The center is meant to be a container for compost for earthworms and other organisms. My understanding is you only want enough material encircling this part to keep it together while you're building the bed. Once the bed is built the dirt surrounding the center will be its support. I would stick to using only stuff that is organic matter--saplings wrapped around the center posts, jute twine, stuff like that which will break down and add nutrients to the bed.

I used cedar fenceposts to encircle it because they won't break down as quickly--I intend to connect some kind of arch from the edge of the bed to these posts to use as vining support to provide shade in the heat of the summer.

I love this hole idea, and your bed does look grate Chris.

Just wondering though weather you could use the cob in the walls to grow more stuff, like strawberries? Mite help keep things even cooler as well.

Thanks Duncan! That's not a bad idea. Strawberries here don't really grow past May though, so I may need to find something else. Perhaps herbs, and wildflowers. I would be really cool to fill it all up with seeds but I'd have to leave room for me to get in and lean on the wall to get to plants in the center. I'll give it a try!