Hugelkultur and Composting

I am new here and have some questions. I'd appreciate your helpful counsel.... I am in the process of building a raised vegetable bed using concrete blocks. It'll be 4' wide, 36' long, and a bit over 24" in height. I'm using standard 8 X 8 X 16 blocks, and think I have a good method to hold the top courses together.

I was going to fill the bed with the topsoil I scraped away in excavating a bit for it, and mix in some finished compost and mebbe some sand. Our soil is normally clay, but it's been improved up in the garden. Anyhow, a few says back I sorta innocently stumbled upon this Hugelkultur business, and it's really got me to wondering. I have more than enough rotting wood to fill the bed right handy. There's also a huge pile of rotted power company trimmings which were dumped 2 years ago, and not only are the chips rotten and rotting, but they're composting as well, thereby breaking every rule of the Carbon to Nitrogen Ratio that I've ever heard. I mean, no way should that stuff heat, right? Yeah, but it does!

My horse farmer neighbor has plenty of fresh horse poo for me to haul. Now I wonder if I should combine the rotten wood chips and some fresh horse poo, put it all in my new raised bed, pile it high, and wait....... Mebbe add the topsoil back next year, after it's sat all winter and compacted itself?

What say ye?

I say I'm envious.

I am not surprised the wood chip pile heats. I guess there is enough nitrogen in the wood to make it happen, not sure. Have you heard of Jean Pain technique? You make a huge pile of wood chips and you run piping through the pile. As the pile heats up, you can heat water. Paul Wheaton has a video about this:



For the horse manure, I would be concerned about it containing persistent herbicides that could stunt plant growth, see this other video from Paul:



Lastly, if I were you I would definitely use all the wood rotting or not to make the core of the raised beds. I would maybe mix in the compost and the sand or just put the soil back on top of the wood, a layer of the compost on top and let a polyculture of plants do the rest of the magic. Here is a third video, this one from Jack Spirko talking about hugelkultur raised beds.

Hey Tim -
Sounds like you have a ready made kit around you - lucky!!! I would probably avoid the utility dropping as most of the poles they use have a coating of penta or creosot that's pretty toxic.
Please keep us posted with your progress and best of luck!

Thank you all very much. I am pretty well sold on filling that bed with rotten wood. I hope to introduce some red wigglers, as soon as it's clear that the mixture's not heating... Seems like a very natural combination, don't you think?

From experience, earth worms will come on their own.

I haven't heard of hugelkultur beds heating up substantially. I think it has to do with the fact that the effective surface area of the logs is not that big in comparison to what you would have with shredded wood. I think that is the same reason why nitrogen robbing is not much of a problem either (it would be if you were to mix wood chips in soil).

Progress Report: This morning finished up the block laying. Also fixed a boo boo I'd made with a "hump" in one wall, well-worth the time to fix, BTW. One thing I have learned is that, when you see you've made a mistake, the time to fix it is the sooner the better. All 4 walls are up. There is a drain hole in the low end, just below the first course of blocks. I wonder, should I install a 4" perforated pipe before I begin to fill the bed? One guy said no, a raised bed dries out too fast anyway..........

I am thinking to begin the process with a layer of 2 year old power company shredder chips. Then add what old rotten logs I can find, stacked so as not to bulge the sides of the bed. Figured to fill in between the rotten wood with the chips too. Mmmm... Mebbe some granite dust in there...... I got a barrel of the stuff from a monument engraving outfit. I think it's good for micro elements........

I just wonder how far it will shrink? I would very much like to plant Fall salad items out there, put it right to work, so-to-speak. On the other hand, sometimes I think it would be better to build a compost pile @ my usual spot, let it work and cook real hard for 2 or 3 weeks. Hot, 21 day compost style, then when it starts to cool, put it into the bed real high, and let it settle over the winter.

Today I bought some hardware items that should (according to plan! ), allow me to fasten the sides of the bed together at the top course. Also, while at the lumberyard checked availability of mix for concrete, as I figure to pour some of the block cores. I have an electric mixer stashed in a neighbor's outbuilding, that will be something of a chore to retrieve, but well-worth it, I suspect.

Will check in from time to time. I am too dumb to post photos, but will get some help on that mebbe sometime....

A guy in a bar told me, "Life is 10% what happens to you and 90% how you react to it." Hmmmmm......

why a drain?

I would keep the chips to mulch on top of the bed.

Ditto what Adrian said. I've never had a problem with drainage in a raised bed hugel, even last year when it rained continuously in the UK all summer.

Unless you put plastic at the bottom (which I wouldn't do) the extra water will just soak into the soil and add up to the water table.

Adrien Lapointe wrote:why a drain?

I would keep the chips to mulch on top of the bed.

Besides letting water out, a drain also serves as a way to get air into the bottom of the pile. When the pipe is not full of water trickling out, it can be full of air infiltrating in. And decomposition fungi rely on that air for their metabolic processes. While there are anaerobic bacteria, there are no anaerobic fungi. Fungi need oxygen, they use it to make peroxidase enzymes that break down their food sources.

This also explains why we don't compact our hugelkultur beds by stomping on them and squishing all the air out.

ah! I see. My thought is that there should be plenty of air gaps in the hugel bed because of the different size of material and as you said because it is not compacted. My guess is that once earth worms start digging through, they will also create path for air to get in there as well.

For anyone worried about aeration, sunflower canes, corn stalks and other quick rotting cane materials have been used at the base and mid section of compost piles to great effect. They leave a void as they rot. I'd be careful with this in dry climates, since too much aeration will dry out the bed.

Another expedient method is to leave plenty of long, thin sticks protruding beyond the surface when a pile is built. After a few months of settling, they can be ripped out for a Swiss cheese look. If I do anything about aeration, this will be it since the sticks are there just waiting to be yanked.

One potential issue with the stick technique in drier climates is that the stick could act as a wick and dry out the bed.

Hi, I have been following the conversation's for some time, and am about to build a hugelkultur bed. I recently cut down a willow tree, like 4 weeks ago. And I was wondering can I use the larger truck sections in the hugelkultur bed. I red in one of the forums that it needed to be dried. If so, how dry, and why.
Thank you kindly for any and all responses.
kathy

Adrien Lapointe wrote:One potential issue with the stick technique in drier climates is that the stick could act as a wick and dry out the bed.

I call them "air wicks". It might be hard to copyright that name.

On willow --- The stuff won't die, or it won't do it when you want it to. Stuff that looks dead can spring to life if rained on. Firewood piles have sprouted leaves. You might find that you've planted a willow hedge. The only way I'd use it would be mixed with lots of chicken manure and leaves to create a hot compost over the entire pile. That should kill it and jump start the decay process. There might be some lag time after it cools before fungi, worms etc. move in to finish the job.

Wow! What a lot of information. It's hard to digest....

I am totally onboard with the idea of a 4" perforated pipe in the bottom center of the bed. I had thought today that, if I go with my idea of filling the bed with a working compost pile, that my leaf blower could be used to inject air through the perforated drainpipe. Wouldn't that be something to see. If I had close neighbors, they'd wanna haul me away......

Scouted today for old rotten logs, etc. There's aplenty. We have heated with wood all the years we've lived here, over 30 now, I guess, anyway there's tons of logs in various stages of decomposition all over the place. A neighbor cut a log for firewood and then didn't get it. Been laying around rotting for years, I'll ask about it, I think he'll tell me to take it......

I do appreciate all your helpful advice on this project. It gives me confidence, I'll keep reporting in from time to time. You keep commenting and suggesting things OK?

Best, Tim M

Re: Air Wick Stick method for compost.....

Sounds like a good idea to me, but I make the California 21 Day compost, and so am turning the pile every other day usually. I make one big pile, usually toward the end of the growing season. My most prized fuel besides horse manure, is spoiled silage. Silage is a high-quality animal feed. When it goes bad, and a lot of it does on a big dairy operation, it's the BEST compost material ever, IMHO. Sometimes it's already cooking when you bring it home. If not, add water and some manure, it won't be long.

I often tell people I won't argue Ford/Chevy Deere/Whatever but that compost really works. I am sold on it, can easily see the difference between our garden as it is now and as it used to be. Drainage/Compost/Irrigation = the Big 3.....

Update: All the concrete blocks are in place for the bed. The crossbraces are installed, there are 10 as evenly spaced as I could get them, bed is right at 36' long. 4" perforated pipe in place, still needs garden fabric taped over it. My pal Kenny came over this evening after work, and in about 2 hours with the help of a mixer and wheelbarrow, we filled 19 of the 20 block cores I wanted filled. I'd only brought 10 bags of Pre-Mix, guess I needed 10 and a half.....

It's very nearly ready to fill. I can't help thinking that my piles of rotten wood chips would be a better thing to fill with then rotten and rotting logs. The chips would be very uniform, and they've been heating for months. Was also thinking that this might be a good place to experiment a bit, mebbe make a portion of the chips, and another portion of more traditional fare for the hugelkultur. Topped with compost and topsoil, natch.....

I am anxious to get the bed filled and back into use. It's almost time for the Fall garden, and we always have better luck then. It only makes sense, right? Cool season crops like to mature in a cool season.

I hope all are well.

Best, TM

Progress Report: All 20 cores to be filled are filled with concrete. Structure appears to be solid. Drain is installed, now covering drainpipe with landscaping fabric and wood chips to hold the fabric. Been scouting rotten wood, there's lots....

Have been busy hoeing and weeding in other areas of the garden, did a few errands, etc., you know the drill. WX has been unstable. Next week can begin to fill bed, will keep you posted if you want.

Best, TM

UPDATE: Began filling the bed today. Found some landscaping fabric, put it inside the walls. Placed a layer of rotting wood chips on the bottom, so as to help hold the fabric. Worked OK.......

Went to woods where I'd scouted some forgotten firewood. Was a Post Oak tree, looked like from a shred of bark left on the stump. The wood was heavy, wet, and very rotten. Some just fell apart, other pieces I split with a light axe. Made me feel like a putz, really, to be stealing all that nourishment from the forest that has been here for so long before humans. I still did it........ Did it Hippie-Style - took some and left some. I figure I'll go back in a month and sow some Blazing Star in there......

Bed is about half full. I shoveled in some soil with the wood. Figuring to add more chips too. The only sore point is a very vigorous ant colony I seem to have imported with the rotting tree pieces. I wonder what will become of them? Has anyone else had experience with ants in the Huglekultur? (Is it anything like bats in the belfry?).

Best, TM

UPDATE: Had to make a run to the trash transfer station, stopped by the farm store on the way home. Found landscaping fabric on sale, bought a big roll. BTW, lawn furniture also on sale. Bought 60 red 2 X 8 X 16 blocks 89 cents each, figured it for a deal. So now the fabric is all in place, and the red tops on the bed walls look pretty good. Will resume filling tomorrow. Anxious to get a third or so filled and planted. Best, T

Wood chips are wonderful stuff (if they are free of toxic yuck), but they work best if used appropriately. If incorporated into soil, they do tend to suck nitrogen as they decompose. You can compensate for that with lots of manure and green stuff, but there may be better strategies. Saving them to use as a mulch is, in my opinion, the better approach: they will slowly rot and add structure to the soil, but because they decompose slowly and on the surface, they don't deprive the plants of nitrogen.

Also, half the point of hugelkultur is to have large pieces of wood slowly decomposing deep inside the bed. This slow decomposition allows the wood to hold water, add nutrients and structure to the soil, and provide aeration and drainage. So using chips instead of logs and branches would defeat the purpose. Too many chips buried in the bed are likely to become water-logged and anaerobic (think stinky slimy rot). I realize that you have added a drain, Tim, but that would not be needed if the bed was based on logs and branches instead of chips.

The bed we built this spring has been yielding strawberries steadily since early July (we've had a cool summer, even for Quebec). It is a log-cored bed with soil shoveled around the logs, all of that covered with spoiled hay and a thin layer of soil and compost on top to plant into. The whole thing was covered with hardwood chips from an arborist. No watering (except for three days after planting the strawberries) and virtually no weeding.

I also use conifer chips on the paths between beds, as they tend to decompose more slowly and tend to acidify the soil, which most veggies don't like. Conifer chips would be great for establishing blueberry beds, which is one of my objectives for next year.

Do be careful about what kinds of wood and slash you add. Trees and vines that have a tendency to re-sprout can be a real headache. Somehow, we got some Virginia creeper stems in there and I've had a heck of a time getting them out from among the strawberries and other plants. I will do a thorough cleanup this fall before layering the new strawberry starts. Other re-sprouting and suckering trees to avoid are willow (as mentioned) and chokecherry.

Good luck!

Dear Heidi,

Thank you for your thoughtful comments. I will try to reply in order......

I agree this batch of chips is great as mulch. I mulched the sweet potatoes, the watermelons, and some of the squash with it. Great stuff! I like to top dress with compost, so have yet to notice any nitrogen robbing whatsoever. I hope to keep using it too, even on the new raised bed.

I hear what you are saying about HK and large pieces of wood vs. the chips. Your setup sounds ideal, and I hope to attempt a more conventional setup sooner rather than later. Sounds like your ducks are in a row... For most of my arrangement, it's already a done deal. I guess I am too much of an experimenter sometimes, but I just figure to give this a whirl and see what shakes out. I topped off the bed today with wood chips. In one end there is some rotted oak, and saw chips from a wood spliting operation next door. Clean stuff.

The other end has another large dose of rotten oak, both are filled in with chips. The middle 8 or 10' of bed is pure chips. I am going to, (Oh, pardon me), let the chips fall where they may... Every vibe I have is it ought to work. Watering is not an issue, there's a pond on the place, and a pump and system in place.

I am soon to begin filling the soil. I am aiming for eight inches of soil at first, and figure it'll settle quite a bit in the first year. I guess it'll be a mix of the original topsoil, a bit of sand, and a generous amount of finished compost. Oh, and some granite dust from a monument company.

I like your idea for blueberries. My wife has tried to grow them for years. As soon as I can, I think I'll try to whip up some pine needle compost. I also read somewhere that there's a corn based kitty litter that's very acid. Like World's Best Corn-based Kitty Litter. I think......

So again, thank you for your kind words. Do stay in touch, and happy gardening!

Best, TM

Update: My "Semi-Hugel Raised Bed" is done! A buddy helped me, we mixed the original topsoil with sand and finished compost. Oh, and some granite dust. Have sown carrots, lettuce, radishes, and spinach. Planted some onion sets right down the center. Hoping I can hold off planting the rest of it, I guess maybe it's almost half planted now.

Thank you all for your helpful comments and advice. I will try to keep you posted from time to time.

Best, TM

I see the last post was August 21st. Holy cats! It was really toasty in August hereabouts. Lotsa near-record temperatures and the rain just stopped. Stopped. Lucky for us the irrigation pump kept plugging away, everything lived, but the germination was awful.

I planted 30' rows of spinach, beets, and kohlrabi, and mebbe got 3 plants of each. Too hot is my guess. The raised bed, semi-hugel is sprouting some spinach, on the third sowing... Have been watering daily, so as to keep the seeds moist. Carrots still no-show, oh mebbe one or two... Radishes germinating sparsely as well....

Looks like the raised bed has quit settling, at least for the time being. No odors, no problems, but it sure seems to require a LOT more water.

Best, TM