Hugelkultur Greenhouse Combination

I had an idea for a way of combining a hugelkultur and a greenhouse that would hopefully maximize the benefits of hugelkulturs and minimize the greenhouse suck factor. I don't have much experience with hugelkultur beds so I want to get your thoughts and ideas on this one. My idea is to use a very large hugelkultur bed as the northern wall of the greenhouse. See the picture for the concept. The northern side of the greenhouse would be anchored to the top of the hugelkultur and then arch over to form the top and opposite wall.

There would be several benefits to this system. The hugelkultur would capture water runoff from the roof storing it for plants thus reducing the constant watering that greenhouse plants require. The hugelkultur increases growing area inside the greenhouse and also would have increased solar insolation during the winter months. In the winter, greenhouses lose a lot of heat to the north side. The hugelkultur would act as an insulating wall to keep the greenhouse warmer. Lastly, if you've worked with small greenhouses you know that they warm up and then loose heat too quickly. The hugelkultur would act as a heat sink for the greenhouse. The heat of the day is captured by the greenhouse then absorbed by the hugelkultur which releases it through the night. Pipes could be added to the hugelkultur to increase heat penetration into the thermal mass.

There are some questions that I have about this. Do hugelkulturs settle or slump as the wood decomposes? Is there an initial period where the dirt settles and then that's pretty much it? Is there something big that I'm missing for why this wouldn't work?

Also, I usually put chickens in my greenhouses over the winter. They take care of any weed seeds and pests that found their way in over the season. What do a flock of chickens do to a hugelkultur bed? Would I have to fence off the hugelkultur to save it?
Thanks.

i was just tossing around some identical things in my mind! perhaps even 2 super hugelkulture beds with greenhouse roof between them and ends.

sounds great to me! the chickens i'm a bit iffy on. in my experience they tend to eat down to nothing if kept somewhere too long. perhaps put a fence down the middle along the hugel bed and switch the chickens back and forth between the hugel bed and the flat side. making it harder for them to eat it to nothing. just a thought (:

Hugels certainly do settle over time, but like an earthworks, how you build it greatly influences that. Pack it well as you go and you'll get much less than if you just pile it up willy-nilly.

I think the hugel wall is a great idea for the thermal wall, but I would run the greenhouse structural posts to ground level (through the core of the hugel) I know there would be a rot/corrosion issue depending on what structure material you use, but I think the right materials could alleviate that, and it would be far better than having one side of your greenhouse settle up to a couple feet.

There are a lot of greenhouses built using earth bermed walls, and the walipini that is built in the ground.
Do you know what sort of materials you're using for the greenhouse? If you build a "normal" greenhouse with a rigid wall on the north side, you could then pile a hugel up against that. Maybe build a cob/adobe wall for the north wall as those are height/structure stable and natural. Yes you would lose the hugel growing surface inside the greenhouse, but you could easily make that up with tiered/layered beds or vertical growing containers.

This is an interesting idea. I have a couple of concerns for the greenhouse longevity. You mention your North wall benefiting from the infiltration of water and thusly providing the sponge phenomena for which we all strive in hugelkultur. The inherent problem is then the inability to protect your structural posts from becoming part of that sponge and seeing your greenhouse slowly fail. Clearly, one would want to avoid pressure treated posts, or utility poles; this leaves Cedar, Black Locust, Bamboo(?). If you were to use those materials, I would suggest following Mike Oehler's advice and use plastic bags and char to protect the subterranean sections. The overall contradiction in design is, you are wanting some wood to actively rot and become a sponge; but, you are wanting the structural posts to be impervious. Perhaps you have access to metal lightposts?

I wouldn't attach the greenhouse frame into the hugelkultur. I think hugelkultur is a great idea inside a greenhouse, but you need your supports to be strong and not move.

Hugelkulturs settle substantially every year. Sepp says that after 8-10 years he comes through with a mini baga (excavator) with a flexible wrist (tilt-rotator) and in one day he rebuilds the whole hugelkultur garden. He doesn't recommend planting trees into the hugelkulturs because of how much they settle. I think that would even more so go for framing members. Plus the moisture from the greenhouse roof will be absorbed by hugelkultur and go through freeze thaw cycles. This is good for your hugelkultur but bad for your greenhouse. My concern is that you'd spend a lot of time trying to repaid the greenhouse as it settles.

dude you should totally do something like that. sweet idea. Like buddy says though, make the greenhouse self supporting apart from the HK.

maybe have HK on both ends? HK taller near north side, and shorter on S side?
poly the HK bed for winter snow? dry soil insulates better i rekons.

plow the way to victory my firenddddddddddd!

Caleb Sturtevant : Peter Clouston has raised the issue of Additional heat loss through evaporation, Our super saturated Hugel-sponge will always evaporate as much moisture
as is necessary to reach equilibrium with the inside of the Greenhouse . This latent heat of evaporation will move heat from the hugelbed into the Greenhouse, BUT as the
moisture condenses into droplets against the colder outside walls the trapped heat will be radiated out through the shell of the Greenhouse !

We also need to consider the fact what a super saturated Hugel-sponge is a large thermal mass that by being so wet does not insulate the Northwall but actually cools it ! This
works against us as it increases the heat load if the Hugelkultur bed is used at the start of our heating season !

We need to look at the dangers of increased moisture concentrations leading to Smuts, rusts, and molds- or increasing our air exchanges with even more heat loss !

This does not mean that this wound not be a very valuable additional greenhouse after your plants have been through/were hardened off ! We just need to Know what we are
getting into ! For the Future of our Craft ! Keep safe/warm ! PYROLOGICAL Big AL ! - As always, your questions and comments are solicited and are Welcome ! A. L.

A problem with Hugel beds settling? Need dirt to hold a lightweight structure? I have the solution: Rapidobe

http://www.velacreations.com/shelter/building-components/walls/item/166.html



For this sort of application, make the base a lot wider than the top, like this /\. Tie the bases of the posts together to avoid them pushing apart over time.

The fabric could be another material, like orchard netting or shade cloth, and you could make holes periodically for plants. The posts will hold it together, and the dirt still gives you planting area. So, in the end, you have a planted wall. You could leave the top accessible to add material (compost/dirt) periodically.

Extra points for making it a wicking bed setup: http://www.velacreations.com/food/plants/annuals/item/108-wicking-bed.html

the sinking problem would be allayed by flexible materials, like a hoop house that would move with it..but rigid materials might be a problem..sounds like a supurb idea

i guess there's lots of ways to go here, and all us people out here don't know all the ins and outs of your situation

i've had a similar idea, only i was going to build an independent greenhouse with a compost pile against the north wall --well, actually between the north wall and an earth berm

i had thought about leaving the lower part of the pile accessible to the inside of the GH where i could remove compost as it became ready, the natural heat of the pile would help keep the GH warm at night, and the daily heat of the GH should keep the pile from freezing-- but to be totally frost free inside i'd plan on a rocket mass heater as a supplement for the colder days, maybe double the rmh as a seed bed germinator in late winter

but hey, my situation is different and that seems to fit what i have, a flexible green house floating on a hugel bed might be just right for you--or one of the other suggestions

it's all good

bob

Here is my suggestion for a hugelkultur greenhouse. https://permies.com/t/27982/greenhouses/Hoop-House-Hugel-Towers

Hope you can see what I am drawing. I think it solves your settling problems, what do you think?

Any updates on this project Caleb? Did you end up building the greenhouse?

I was thinking of building a seasonal greenhouse/coldframe in walipini style, between two hugelbeds. This requires the space between the hugelbeds to be wider and a meter or so below ground, which means it needs to have proper drainage, but it takes full advantage of ground insulation.

Thoughts?

Caleb inspired me and I built something very similar to this! I already had a 16x24 hoop house frame to work with. What I did was dig down about a foot on the downhill side and leveled out from there (about two feet down on the uphill side), drove galvanized posts in to support the frame about five feet above my new grade, slapped the hoop on top and built 3 foot tall raised beds with a woody core (hugel style) on the south, and west sides. On the north side I built a hugel mound that extends beyond the outer edge, but contained on the inside. I'll try to find some pix to so it makes more sense, but its working pretty darned good. So far in two winters it hasn't fallen bellow 14F despite outside temps as low as -10F. I figure I've gone from zone 6 to zone 8 in there, not too bad in my opinion.

Hedge (aka Bodark or Osage Orange) would do fine as a post inside a HK. The other option might be to have your hoops rest in pvc with holes cut to accept the ends. The base would settle with the HK until the bed demands a rebuild. However it is accomplished having the side float on the HK seems better than having it fall away from a post a little each year

interesting idea

This kinda reminds me of tefa (textured earth food all-year-long).

oooo! really like this =)

well got my brain wheels turning =) i can vision some interesting variations with a similar idea...with tiers and steps and lots of vertical levels.

Here's a couple pictures of what I came up with in this space:

And a couple more of the construction phase:

The end walls and sides have since been sealed up and plenty more hugels, swales, and grow beds set up around to create more micro-climates. A fair bit of TEFA going on down there, and plenty more to come.

Interesting information - Thank You! I'm in process of making Hugelkultur mounds in my greenhouse. One started and one area identified for another. Neither will be very big, but I think the heat creating force of the mounds will help the greenhouse be a heat sink in front of my house.




Two posts will require rock to block soil intrusion on the posts.

Here is an aerial view of the greenhouse interior, mapped. The two holes noted will become foundation for a raised bed for asparagus - it will be a wood framed rectangular bed constructed over the holes which are filled with sandy greenhouse soil amended with abono (cow poop).

The mini hugel projects in the greenhouse have commenced! Tearing apart former rock wall/support to dig the base. Topped off and seeded one round mini-hugel; need to place rock between it and support post.

Slideshows here

Update This past week’s activities concentrated on re-purposing the area inside the greenhouse my greenhouse transforms...

Began digging the space for the hugel base this morning. I think the base material is Uruguay's famous depleted soil. Greasy, clay like... update with progress photos

Moved out that ugly heavy silty compact depleted "soil" I had cut up yesterday - here's a shot of two types in my hugel update today ..

What I want to do is begin putting the hugel together, but I'm more interested in seeing how the trench manages the rain before I fill it with wood & stuff. we may get rain this week. I can collect more materials for the hugel in the meantime. And, if it does rain, I'll be able to cut the trench down more. I like the idea of deeper trenching inside the primary hugel cut. Most of the hugel construction I've seen the base is basically level.

Does it matter?

I dug a trench down another foot or so through the middle of my beds that I built for the hoophouse pictured above. I think that it helps to channel the water into the core area of the beds instead of seeping to the outside edges. My theory is that this will help to keep the beds hydrated longer. With the sunken walk area of my greenhouse I tried to do whatever I could to keep any moisture moved under the hugelbeds instead of in the walkway. I've noticed that I can pump a lot of fluid into those beds before there is any spill over out into the walkways. I think the level based hugels are constructed that way mostly for speed and ease of construction. The beds I created on the outside of the greeenhouse are more traditional in shape and appearance and where constructed with the level base. Those beds definitely shed more water which collects near the base, and can get a little sloppy sometimes.

Dave Dahlsrud wrote:I dug a trench down another foot or so through the middle of my beds

I was also thinking about water "habits" and with the right angling I think I can further prevent water from heading under the house. and, I think too, the sections between the deeper trenches will assimilate the resultant oozing dynamic juice soil and soil working critters with the wood on both sides and above as opposed to just being above. Thanks for sharing your experience.

A couple of years ago I came up with a variation on this concept. It worked out great. The variation was this: Instead of a full greenhouse, it was just a low tunnel for my seedling flats. Instead of a raised Hugelkultur bed, it was Hugelkultur in a pit.

Let me explain: First you dig a pit and fill it with wood. Next step is lots of fresh manure and some free coffee grounds from StarBucks all watered in and tamped down until the manure fills all the gaps. Then cap the pit to ground level with about 2-3 inches of top soil saved from digging the pit. Last is a layer of leaf or wood chip mulch. Over the whole thing I put up about a 3 feet tall low tunnel.

Here is how it works: The heat and CO2 released from the decomposition of the manure provides just enough warmth to keep my spring seedlings warm and growing fast. Not enough to stop a hard freeze, but plenty to stop any light frosts and the extra CO2 helps to make sure the seedlings grow fast and healthy. Later once my tomato seedlings are in the ground, I plant warm weather crops like watermelons. I will leave the low tunnel in place until real consistent warm weather. I gain at least 2 weeks to a month growing season for melons this way. Last I remove the low tunnel and grow normally.

Works here in Oklahoma. Might not be enough in really cold areas..but sure it would help. Surprisingly the ground never slumped back down. It has stayed completely level so far going on 3 years. If anything it might be slightly raised compared to the rest of the garden. I have no explanation for that. It's some REALLY good soil there though.

Scott
I really like this idea. I was planning on putting in a propagation bed this spring/summer and was going to do a raised bed, but now I think I'm going to go this route with it. I bet those beds stay nice and moist with a pretty high humidity...sounds like a helluva combination for doing soft wood cuttings. Thanks for the inspiration...man I really like this thread! First the greenhouse idea and now my propagation bed, thanks Permies!!!

I put together an article detailing my results using a combination of hugelkulture with a greenhouse, along with my construction and design process that I went through. I've had what I believe are quite exceptional results with this combination, and I think they might just be a perfect pairing. Using hugelkulture in the greenhouse really does a bunch to mitigate a lot of the "Suck Factor" Paul talks about.

Here's the link: http://traditionalcatholichomestead.com/greenhouse-project/

Dave Dahlsrud wrote: I couldn’t wait to plant stuff… just had to do it!

lol... completely understand that feeling! still reading your article... that is really nice, 2 Zones! I wonder if you built hugels on the outside alongside the walls you might increase at least another zone!

A lot of good ideas. IF you are still wanting to do a complete, traditional greenhouse, I would suggest that any structural members that are going to touch the hugel should be made of stone, block, or concrete. this would increase thermal mass, and alleviate rotting concerns.

Will Scoggins wrote:A lot of good ideas. IF you are still wanting to do a complete, traditional greenhouse, I would suggest that any structural members that are going to touch the hugel should be made of stone, block, or concrete. this would increase thermal mass, and alleviate rotting concerns.

what if you did not have access to rock, concrete, blocks, etc... the one side of Dave's greenhouse without wood, just the hugel on the edge under the plastic.... has me thinking - what if the only materials besides the hugel itself is the the frame (pvc over rebar struck deep) for the roof/walls?

If you want to experiment, go for it. Simple solution is permanent posts in the center of the mound, Mulching and adding matter can supplement shrinkage, I'd be more concerned on how to keep the glazing tight, not sinking structures. A hugel-bermed permanent wall makes more sense, but kinda defies that point of not building a wall. Maybe a bioshelter is your thing? http://bioshelter.com/

chad Christopher wrote:If you want to experiment, go for it. Simple solution is permanent posts in the center of the mound, Mulching and adding matter can supplement shrinkage, I'd be more concerned on how to keep the glazing tight, not sinking structures. A hugel-bermed permanent wall makes more sense, but kinda defies that point of not building a wall. Maybe a bioshelter is your thing? http://bioshelter.com/

in several latin american countries I've seen/see concrete/mix rock (small to gravel small) as fence posts - they last much longer than wood. metal frame work (rebar-like) rectangular interior.

In my travels in central america, I have seen entire multistory hotels build out of nothing but rebar and hand mixed concrete, from beach sand and pebbles. ....locally sourced.

chad Christopher wrote:In my travels in central america, I have seen entire multistory hotels build out of nothing but rebar and hand mixed concrete, from beach sand and pebbles. ....locally sourced.

Yeah! This as well. I was just thinking posts for hugelhouse...

need more branches, leaves/greens and soil to complete the greenhouse hugel - this is where it is now in development

The solution that I came up with for combating the shifting hugel making the greenhouse unstable was to utilize the galvanized fance posts to attach the framing to. The hugel on the North side has a row of posts down the middle and the hugel just settles around it. I've had no problems keeping the glazing tight with this system so far. I realize the posts will eventually rot away, but that should be well after it's time to rebuild the beds and replace the glazing anyway. At that point I should have about 20 yards of primo garden soil I can take from the system to use else are and a fair bit of wood from the raised beds to use in new hugels. Creating awesome soil and tomatoes at the same time... not bad function staking!

that sounds good... I paid for help to build the greenhouse frame and they didn't follow my design (even tho they requested it) so I have to adjust around the post/feet issue and use "dropped elevation," drainage and heavy rock support to protect and secure my greenhouse foundation. I wish I were 20 years younger and without knee breakdown or that I could clone myself.