Feedback Wanted: The Grow-Cano

While working up at the Lab today, I considered how to come up with a built structure geared towards growing plants, very much like hugelkultur. Personally, I'm looking for something not as large as a typical Wheaton Labs hugel, and is easy to maintain and keep everything in reach for the average person (or the lazy person, kinda like me). I checked-in with both Paul and Fred about this, and they admitted they haven't seen anyone else trying something quite like this, so I'm checking in here at the forums for feedback.

I currently call this the Grow-Cano (think "volcano"). It's a mound about six feet tall, 12 feet wide, and has a center column comprised mostly of wood, with a cap of about a foot of gravel. The general idea is that you irrigate the mound by dumping water on the gravel cap. This results in the water infiltrating the center of the growing mound, with the intention of having it permeate the entire thing. It's made entirely of natural materials, and it will persist through both the hottest and the coldest times of the year without damage (like those clay pots that people recommend time and time again...).



Questions for you:
- Do you think this is a horrible idea? If so, then what makes you think that?
- Has anyone else done something similar?
- Do you see any potential problems that ought to be addressed for the next version?
- Finally: thumbs up, thumbs down, or ehh... ?

Thanks for your input...!

I think this is a great idea. I could be wrong. We won't know until you try it!

If I'm understanding correctly, it's basically a small hugel with dedicated watering spot for wicking action watering?

I think a key will be filling the core, especially around the wood, with very absorbent leaves and compost or soil. That should help it get up and running asap I would think.

Be sure to put some lava rock or pumice in there.

Grow-Cano sounds muy bueno!

A vertical hugel?

I'm intrigued. The wood (once it turns punky) will act as a sponge in the core at least in theory.

I wonder about shrinkage over time in the core and how the mound will respond. I suppose in time the whole thing will fall inwards to a degree and just become a slightly smaller mound.

In my mind, it is worth exploring.

What comes to mind to me is that perhaps this is to the same effect as Mr. Trotter’s hugel paths (https://permies.com/t/157279/Hugelpath). Dig down and hill up on the beds and keep adding mulch in the paths. Then when rain comes the paths soak in moisture, and they are in the right place (in the trench or the path) so that they fill up.

I could see the gravel becoming an issue for if you ever wish to put a spade into the mound. It might be just as good to have wood chips or woody debris at the top.

There’s also the issue of getting on top of the pile to pour water in. If one were to have deep mulched (or hugeled) paths then the water would flow into the appropriate section and not need to be carried up a slope. But, if you have water stored higher than the cone (or pressured) then this would not make a difference.

These are just the thoughts that come to mind. I am interested to see what will come of it!

Maieshe Ljin wrote:I could see the gravel becoming an issue for if you ever wish to put a spade into the mound. It might be just as good to have wood chips or woody debris at the top.

I'd decided to opt for gravel to "cap" the center so there's more of a chance that it will stay clear of organic matter and growies to make it easier for irrigation - at least at its inception. Over time it might prove problematic, as you say, when I want to renovate/doctor it. We shall see.

Thank you for the link to the hugel trenches thread...! Well worth a look and inspiration. Initial efforts seem to have been promising with those.

Maybe I could set a fire at the center of the grow-cano to generate some bio-char in there? That seems difficult to monitor/standardize, though. Would be fun to see, I think. :)

Neat design!
I think things growing in the center is a good sign.
You could even seed the wood core with nitrogen fixers.
Chop and drop as needed.
If you really don't want anything growing up there maybe use a big flowerpot/olla or a bucket with a slow leak ?

Seems worth trying. I'm imagining twenty years in the future, the wood has rotted substantially and the gravel is now all through that center column. What do you do then? Is that an asset or a liability?

Interesting idea. It reminds me a bit of a 'slow' banana circle - central organic material feeding outer hungry plants. An alternative to gravel may be just to have twigs sticking out the top. If they are proud of the surface they are more likely to stay clear of 'growies' and will not make a plug of inorganic material.
I wonder whether feeding it with grey water (if you had enough head of pressure) would work, or be desireable? I gather that is one of the functions of the banana circle. I wonder what other functions one could stack?

I'd substitute chunky biochar for the gravel if I wanted a watering channel that wasn't prone to clogging up. That way, when it comes time to decommission the thing, you don't have rocks in your otherwise magnificent soil.

Phil Stevens wrote:I'd substitute chunky biochar for the gravel if I wanted a watering channel that wasn't prone to clogging up. That way, when it comes time to decommission the thing, you don't have rocks in your otherwise magnificent soil.

Ooh, good idea! Make it uncharged to keep plants from growing in it too.

I think it's a great idea Stephen!  I'd consider not having the channel go all the way to the original ground.  Irrigation may just go down there and have trouble wicking back up to the top half of the growcano.  Maybe have it only be 2/3rds the total height of the growcano.

You could maybe also consider a layer of sticks in a spoke pattern at the bottom of the irrigation channel to help water work it's way outward in the mound.

Thanks to everyone for their feedback so far...! I'll make some revisions to the initial plan as follows:

- hole about 2/3 the way down into the mound, though still full of mostly wood
- wood chips and char as the cap of the hole at the top

There's a mound where some Boots had dug a "crater" at the top of it, and I think this will be the place I will start a prototype. It was actually looking at that mound in particular that started me thinking in this direction. I checked in with a couple former Boots who had seen the same site, and they also gave me some feedback in a similar direction. So outlook is good.

Again, I appreciate everyone taking the time to drop a note, some questions, or additional ideas in here. Thanks!!!

I don't think it's worth pursuing, as the majority of roots tend to stick around in the top 30 cm or so of soil, right?    

Assuming this root zone as the target, I perceive it will take too much water to first saturate the entire wooden core, and then slowly percolate outward horizontally (hydraulic pressure) and downward with gravity all the way throughout the cone to the edges where the plants are, compared with just watering the immediate root zone to begin with and having organic matter nearest the rootzone.

In other words, the volume of the dirt cone is quite large, compared to the top foot or so of growing space, that's a lot of soil to percolate through, requiring a lot of water.

George Yacus wrote:I don't think it's worth pursuing, as the majority of roots tend to stick around in the top 30 cm or so of soil, right?    

A lot of them go sideways quite a bit though - think of comfrey! My comfrey has roots going several feet in both directions. I suspect if there was water there then the roots might be inclined to mine it.
It may be worth selecting the plants on the sides appropriately though, or letting them self select by wildly spreading a selection of seeds and getting survival of the fittest....

Neat idea.
Potential problems : the water doesn't go the way you want.
It can go too deep or not deep enough, it can go sideways, it may have a side that requires more water than the other because of plants, winds or isolation.

How do you see a spiral infiltration ditch?

So, has anyone tried this volcano style method?  If so, I’m curious how it is going.

Two mornings ago my place was hit by a tornado.  In the yard and driveway I lost multiple 90-ish yr. old sugar maples.  Some snapped and some laid over from the roots.    These old maples were hollow.   As I cut them up and have the tree service guys help with what I cannot, I want it to be done with intention for their used (not just firewood).  This volcano-style might be a natural for some of the hollow trunk material.

Thoughts?

It would be great to hear back from Stephen to see if he made this Grow-Cano and how it is doing.

How does your garden grow?

Anne Miller wrote:It would be great to hear back from Stephen to see if he made this Grow-Cano and how it is doing.

Thanks for asking about it. I think gardening is one of the most exciting and interesting things we do out here at WL.

To sum it up, we had a mild winter round here this past season, however in late December we had a terrible windstorm that knocked down maybe 75% of the fencing at Allerton Abbey, which is where the prototype site for the Grow-Cano is found. We've held off on aggressive garden prep up there because without fencing, the deer treat us like a complimentary vending machine and just punch buttons until their food falls out. I really don't feel like feeding deer these days.

The good news is that since we have more hands on-site, fence repair is nearing completion. The rest of the team and I ought to have something to show for the Grow-Cano in time for late-season planting. We'll see.

“ … in late December we had a terrible windstorm that knocked down maybe 75% of the fencing at Allerton Abbey, which is where the prototype site for the Grow-Cano is found…”

Ooftah !  That blows.  Thank you for the reply Stephen

Ok, well, I may just try my own design now that I have an abundance of downed trees.  

I also have a mountain of cow manure/hay from this past winter.  Would this make a workable substitute for soil?  Too hot?  (No herbicides used on hay fields).

I would be concerned if the entire trunk was used that it might take too long for the water to penetrate to the soil near the top. If it was pieces of the trunk, I think it would be good to experiment with.

If water is percolating too quickly, you could use an olla.

Matt McSpadden wrote:I would be concerned if the entire trunk was used that it might take too long for the water to penetrate to the soil near the top. If it was pieces of the trunk, I think it would be good to experiment with.

Yes, it would be pieces of the trunk, cross-cut sections    These are large circumference trees.  For scale: 2nd story roof at lowest point of slope is 30’ from the ground.

L Robertson wrote:

Yes, it would be pieces of the trunk, cross-cut sections    These are large circumference trees.  For scale: 2nd story roof at lowest point of slope is 30’ from the ground.

I think it would be great structure to hold up the grow-cano, but if watering from the middle, I worry the water would run out the bottom before it could be absorbed from the side. Maybe if the bottom was plugged... and several slices were used rather than a single piece of trunk. Then the water would stay in the middle long enough to seep out the cracks and provide water. The plants could even grow their roots into the middle like a grow tower maybe.

Matt McSpadden wrote:

L Robertson wrote:

Yes, it would be pieces of the trunk, cross-cut sections    These are large circumference trees.  For scale: 2nd story roof at lowest point of slope is 30’ from the ground.

I think it would be great structure to hold up the grow-cano, but if watering from the middle, I worry the water would run out the bottom before it could be absorbed from the side. Maybe if the bottom was plugged... and several slices were used rather than a single piece of trunk. Then the water would stay in the middle long enough to seep out the cracks and provide water. The plants could even grow their roots into the middle like a grow tower maybe.

Yes, that was what I was thinking, like a hugel grow tower.   I can build the base wide with plenty of log layers as Paul shows, but in a square, and then the trunk cross sections towards to top, of each steppe layer,  like planters .  ? 🤔

L Robertson wrote:
Yes, that was what I was thinking, like a hugel grow tower.   I can build the base wide with plenty of log layers as Paul shows, but in a square, and then the trunk cross sections towards to top, of each steppe layer,  like planters .  ? 🤔

Nice. I think that has potential... but I am not a hügelkultur expert by any means. I think you should build it and start a thread documenting it with pictures (we love pictures). And then you can tell us if our theories pan out :)

This project reminds me of the ARK bed - African Raised Keyhole bed with a tower of compost in the middle where they pour greywater as well.

I think that your version would have more chance of working in my ecosystem than the Keyhole bed did. That said, I had deer pressure and was relying only on compost, rather than compost + greywater.

I can totally understand your frustration with deer...

This is basically how we dealt with large oak stumps in our yard, by surrounding the entire stump with deadwood, compost, soil and leaf litter. Initially we poured water and compost tea in the center crevices to encourage decomposition. Eventually I chopped a 10" hole out of the center for an apple tree, but the space completely filled with oak bracket fungus and choked out the apple sapling. The hole was cleared, and replanted with sage.

A year later I transplanted the healthy sage elsewhere and enlarged the hole, which by then had rotted all the way down to ground level. A new apple tree took center stage, with room at the top of the hole to hold water. It doesn't stay there long; watering the apple tree waters the entire mound.

As you can tell from the pictures, it is a constant challenge to keep organic material mounded up against the stump. Deterioration has been relentless, with soil washing down after every rain. Fortunately, it also makes the planting area around the stump especially fertile. We've grown beans, onions, peppers, strawberries, potatoes, sweet potatoes, herbs and now sunflowers.

The only other problem is one we've found with every hugelkultur project we've tried, and that's dealing with the empty voids that occur beneath the surface. Underground wood rots away, leaving roots dangling in a dry, empty space. The first clue is usually a dying plant, while everything around it flourishes. I've now made a regular practice of poking our hugelkultur mounds with a broomstick to locate empty spaces. These get refilled with soil and compost.

From this experiment, I imagine the biggest challenge to a Grow-Cano would be keeping the sides of the mountain from washing down. Otherwise, it should work very well to increase the amount of cultivated space in a small surface area.

Yeardly Arthur wrote:This is basically how we dealt with large oak stumps in our yard, by surrounding the entire stump with deadwood, compost, soil and leaf litter. Initially we poured water and compost tea in the center crevices to encourage decomposition. Eventually I chopped a 10" hole out of the center for an apple tree, but the space completely filled with oak bracket fungus and choked out the apple sapling. The hole was cleared, and replanted with sage.

A year later I transplanted the healthy sage elsewhere and enlarged the hole, which by then had rotted all the way down to ground level. A new apple tree took center stage, with room at the top of the hole to hold water. It doesn't stay there long; watering the apple tree waters the entire mound.

As you can tell from the pictures, it is a constant challenge to keep organic material mounded up against the stump. Deterioration has been relentless, with soil washing down after every rain. Fortunately, it also makes the planting area around the stump especially fertile. We've grown beans, onions, peppers, strawberries, potatoes, sweet potatoes, herbs and now sunflowers.

I love this idea! I am soon to be the steward of about 7 stumps (removing some trees for future build area). The downfall…they are all Tree of Heaven which is an entirely unpleasant tree from what I am learning. The tree, specifically the roots system, is allelopathic but, I have read that those conditions die after a year of decomposition. No idea if it’s actually true.
I want to incorporate this idea. The area of the future stumps will double as one of my chicken pastures. It would be great to grow food for them utilizing the stumps. Any chance you have experience with this method and allelopathic trees (black walnut or tree of heaven) or any advice on experimenting with them? I assume I’d have to help them decompose and give them extra time before trying to plant anything but, any suggestions for encouraging the process?

Stacy DeRemer wrote:... Any chance you have experience with this method and allelopathic trees (black walnut or tree of heaven) or any advice on experimenting with them? I assume I’d have to help them decompose and give them extra time before trying to plant anything but, any suggestions for encouraging the process?

I do not have any experience with tree of heaven specifically, but I do have experience with cedar and white pine which are said to be mildly allelopathic. In my experience neither is as bad as some people say. And both did not last very long after cutting. If anything is growing by the stumps right now, you can grow more. For faster decomposing I would drill a bunch of holes in the stump and plant mushrooms... or else just cover it with dirt and leave it for a while.

Thank you so much Matt! Amazing suggestions. There is never a time that I couldn’t use more mushrooms. Some how I’m more excited, didn’t even know it was possible.

Stacy DeRemer wrote: The downfall…they are all Tree of Heaven which is an entirely unpleasant tree from what I am learning.

Yes, the tree may be wonderful in its home ecosystem, but it's pretty aggressive.

The tree is capable of reproducing vegetatively

is a concern from this webpage: https://www.invasivespeciescentre.ca/invasive-species/meet-the-species/invasive-plants/tree-of-heaven/
I thought I had heard this about it. That suggests that covering the stump with dirt might not kill it, but just encourage it. The idea of growing mushrooms on it to weaken the stump, seems like a better suggestion!

There are trees that will up and die if you chop their heads off, but there are also several trees I've met that think this is an invitation to regrow as a pollard or a coppice or a clonal colony.

Jay Angler wrote:

Stacy DeRemer wrote: The downfall…they are all Tree of Heaven which is an entirely unpleasant tree from what I am learning.

Yes, the tree may be wonderful in its home ecosystem, but it's pretty aggressive.

The tree is capable of reproducing vegetatively

is a concern from this webpage: https://www.invasivespeciescentre.ca/invasive-species/meet-the-species/invasive-plants/tree-of-heaven/
I thought I had heard this about it. That suggests that covering the stump with dirt might not kill it, but just encourage it. The idea of growing mushrooms on it to weaken the stump, seems like a better suggestion!

There are trees that will up and die if you chop their heads off, but there are also several trees I've met that think this is an invitation to regrow as a pollard or a coppice or a clonal colony.

Thank you so much for sharing that information. I think I’m going to try a couple of experiments on them once they are cut. I do love the mushroom idea so I’m going to try some oysters on them since they are so hardy. Fingers crossed!

I have the same idea !

Here is what I now have.

It used to be just a pile of soil and weeds and one day
upon finding the basin and bin, decided to do something
about it.

So I cleared everything into buckets and boxes to another
corner of the balcony. I ringed the area with bricks and
flowerpots. For the walkway around the railings, I spread
wood chips. Then I just filled the basin and bin and the
space in the middle. I left a tube inside the bin for some
future purpose. I also embedded tubing in the centre. I can
later add a pole or mast here and maybe use it to hold up
cherry tomato plants.  Or an umbrella.
If you look carefully, beans are the
current crop. I have cut drainage slots into the basin and bin.

Behind the ladder is where the former soil is stored.
There are also 3 or 4 buckets of
*cough* over 10-year old humanure *cough*.
I haven't had time to shift this humanure and soil into the
basin, bin and surrounding since there are always pressing
matters like the neem tree dislodging a roof tile and rain
was dripping into the bedroom. Once I finish, there will be
a volcano hugelkultur there. Humanure, pottery shards,
biochar, leaves. Once this becomes substantial enough to
wick water into the flowerpots, I will add earthworms. The
best news right now is no snails.

But priorities.

This is why there is a ladder there. I usually do a sturdier
job of attaching a vertical banister to the ladder but this
was enough to get me off the roof safely without kicking the
ladder away. Note the hash marks in the middle of the ladder.
That's roughly where the centre of gravity is.

It so happened that the gutter rusted and a hole developed.
Instead of repairing this, I allowed it to drain into a
polystyrene box. Drain holes are at the bottom. I later added
a 5-gallon bucket and a floral stand. This breaks up the water
stream.

I have not sealed the balcony but by the time the concrete
deteriorates, it will be someone else's problem.  

I still do a very limited humanure. See the slotted spoon
and saucepan? If you know, you know. Below that piece of
plywood is some humanure. Sometimes you just know that
the flush won't cut it. So I place it there and pile used
coffee beans around it.

I keep some used coffee beans in the bedroom and bathroom.
I think it helps keep the mosquitoes away - - - at least
noticeably better than before.