Cold-climate hugelculture -- better on-contour or off-contour?

I am thinking of putting in some hugel beds this spring. A lot of people talk about doing them on contour, but I also seem to recall someone (Paul? Sepp?) mentioning the benefits of doing them off contour in colder regions. i think the ideas is that something at an angle to contour could let the bed shed cool air rather than creating frost pockets. Obviously, the downside is that having them off contour diminishes the swale-like effect. Thoughts? Experience (good or bad) with doing them off contour or having them hold frost? (I'm zone 4/5) Thanks!

We have your temperature, but...

What is your rainfall profiile? How much yearly and how much comes during the growing season?

What is your solar aspect of the slope? What would be the solar aspect of the beds? Will they run N-S or E-W?

How big of a system are we talking? Twenty feet of hugel or 2000?

Everything is a tradeoff. Trying to figure out if you need thermal gain or water retention more.

There are ways to make them as swales with level sills that act as cold air dumps, too.

Like R Scott said lots of variables at play. I just put in my first hugels, and went off contour for several reasons.

I wanted the beds to run North-South for the solar aspect.
I wanted the beds to drain frost downhill, and not pool up cold air.

My hugels are about 80 feet long, 5 feet wide.
I have no water retention needs, having abundant irrigation. My bigger objective is about warming the soil. And of course the fertility gains from hugelculture.

Cant say how good an idea it all will be, but I'm optimistic. I had my garden beds running the other way for the past 7 years, and that experience led me to switch it up.

Good luck to you, and me!

Good questions / suggestions. Annual precip is about 20-25 inches. Most of it comes Oct through June and then July-Sep is very dry (as in often no rain at all). Soils are very deep and mostly silt, so I'll be needing to build lots of organic matter. Beds ill be on a north slope, but not a steep one. They'll still get good sun in summer, especially at the higher parts of the beds. Beds would be running mostly E-W if I do them on contour. For the time being Irrigation will be limited to what I can haul to them in 275gal totes. Size is a good question....The ultimate goal, if this is the setup I go with, would be maybe 500' long each (although they could be broken into sections for cold air dumps, etc.)

One more question: Could you have a pond above them to provide irrigation?

Or maybe you could do one on contour up high, sacrificing it to cold in order to infilitrate water and then put the rest based on solar exposure.

in Michigan I had some drought problems with my n/s hugelbed last year..I ended up buying a soaker hose and using it on top as it wasn't wicking well..maybe my wood wasn't rotted enough??

the WEST side of the bed grew things much better than the EAST side did..esp cabbages and greens..lettuce grew like crazy on west side..the east side grew nothing well.

that was year one with the hugel bed..maybe this year it will do better

A pond above might be possible, but it would essentially be in a dip at the top of a ridge, so it wouldn't have much of a watershed. Another alternative would just to plan a small irrigationline along the top or through the middle of each one so that I could easily plug them into roof cachement or something later on. (That might be a year or two though...at this point there are no roofs.

For orientation, I was thinking less of going ful N/S and more like just putting them off contour slightly. Two options I had thought of so far.

One was to 'fish scale' them, so rather than having very long hugels, I would just make them (making up number for sake of discussion) 50 ft long, then have a gap of 50 ft, and then do the next 50ft long hugel -- but still staying on contour. If I do another set below them, I would make them offset, so the one below would catch any extra water that had run down from the gap above and any cold air sliding down the hill could easily pass through the gaps.

Alternative B was to just take the hugels slightly off contour so that instead of being trapped any cold air would slide down the hugel and off the end. This approach seems like it would be less effective, especially as the bed got longer. Hwever, it could potentially be combined with the first option to help the cold air move past.

Anybody tried anything like that?

Simply: Once your wood rots down a little, the sponge effect will increase the water retention. You can cut down frost pockets by stacking the back side(uphill side) of the hugel with dark coloured stone acting as a thermal shield, this will also act as a dew condenser, increasing irrigation.

Expanded: I was having the same problem with a fresh cut cherry wood hugel I built last year, having to water it like crazy during the hot spells, to prevent wilting and plant die off.
Towards the end of the summer I ended up replacing a roof on our pump house, which was composed mainly of old plywood and donnacotta(low density fibre board), finding that the local landfill merely burns every wood product that's dropped there, I opted to build a hugel out of the discarded material. The plywood was pretty badly dry rotted and the donnacotta was already like a sponge, after watering it once and burying it I didn't have to water it again despite a three week 30C-40C degree hot spell, currently recharging under snow pack, and it most likely won't last long, but it was a good example/contrast of water retention based on material porosity.

Side note: I plan on inoculating the donnacotta/plywood hugel with pine mushroom next year just to take care of any toxins that may have been present in the glues or treatments in the material, It's probably not advisable to cycle old construction material down with hugels, or at least anything more hazardous than wood products, I won't be consuming the mushrooms that will grow out of it or be planting food plants on it anytime soon, I've pretty much let the native plants take that hugel over, and they seem to be thriving, the cottonwood sapling growing twice as fast as their siblings nearby.


Hope this helps


-Dylan

I'm going to try some small hugels this spring intentionally off contour. It will enhance better n/s sun exposure and facilitate or allow drainage. good luck with your project!

Re-reading some Sepp Holtzer last night......he actually emphasizes doing beds off contour so that the lower ones don't try out.

You're way ahead of me. I figure every place is going to be so different anyways there will always be room to experiment:)

peace & happy growing!

I am very happy to locate this thread as I am really trying to picture what a hugel / swale cold climate set up would look like. I was just listening to one of the podcasts -- #228. Paul and Geoff Lawton are talking swales. Size and depth. And I think they chat on / off contour (maybe not). I wrote down that Paul said 8 - 12 inch depth for the swale in a cold climate. But I don't know if that was for on contour or off... or both.

I will post my specifics --
Slope is 10 - 15 degrees from NW to SE
Average annual temperature 52.8 F
Average annual rainfall is 39.4 inches. With 27.7 inches of snow. (I admit I am not sure how to locate how much of this falls during the growing season.)
I have not put the beds in yet, but if they run N-S they would be 200'. If they run E-W they would be 60'. (E-W would be contour) These would be pretty tall. The land has a lot of rotten wood from old trees. So maybe 4-5' tall.

I guess my two main questions are (1) Does the bottom of the swale butt up against wood or soil? (I hope this makes sense or that I can explain better). Let's say I put in a swale E-W. I take my shovel and start to dig the swale at 12'' deep. Would I dig another trench (down slope) to toss the logs in then cover? OR do I dig my 12'' swale and put the wood (again down slope) on top of the soil? I was thinking in order for the wicking action of the hugel to work the water would have to have access to the decaying material. Most of my soil is clayey loam.


(2) Is there a way to both capture the water and let the cold run run downhill? These two things seems mutually exclusive to me. (Again a concept that is tough for me to visualize). If I were letting the cold air go wouldn't that mean I was off contour and therefore wouldn't be able to hold water? Should I even worry about water because of the rainfall in my area? Because of the size of the hugels and once they are in place for 2 years I won't have to worry about it anyway?

A.J.

ave annual rainfall: 110
ave annual temp:max=48.2, min=35.2

oops=forest!

I know, it's hard to see the contour here, it varies & is more dramatic south of this spot (underneath the fallen trees). No lack of hugel material here. Top soil will take some time....

Would it make sense to put shallow swales (6-8" deep) on contour and build hugel mounds periodically along this swale? The swale would hydrate the soil and charge up the hugel mounds but there would still be lots of room btwn the mounds for frost drainage.
I'm looking at a similar scenario in zone 3.

Just browsing around this site, getting tons of exciting ideas. I love how permaculture is basically a mimicry of nature, and allowing natural systems to do the "work". In that regard, I have taken to leaving felled trees on contour to rot.

In our area of coastal CA we have a lot of coast live oak trees dying from oak root fungus. I used to take them down and get them cut up for firewood, with the old principle of "sanitation" in the back of my mind. Now I just leave them on the ground to rot and collect debris uphill. This is, I think, the original hugelcultur, with no work and certainly no heavy equipment. Can't improve on Nature!

Don Eggleston

A.J. Gentry wrote: I was thinking in order for the wicking action of the hugel to work the water would have to have access to the decaying material.

In one of the videos from Geoff Lawton's PDC, he shows a swale and the uncompacted mound of soil below the swale. I think he showed how the mound was wet at ground level and several inches above ground level, because it was wicking water up. He then said that was the only way you could make water move uphill - defying gravity - was though the capillary action of the uncompacted mound.

This was not a hugelkultur though. I'm not sure if it would work the same. The wood might break the capillary action, I don't know. I think an HK would hold water like a sponge but I'm not sure about wicking.

For your other question I don't think you want any exposed wood in an HK.

Cj Verde wrote:

In one of the videos from Geoff Lawton's PDC, he shows a swale and the uncompacted mound of soil below the swale. I think he showed how the mound was wet at ground level and several inches above ground level, because it was wicking water up. He then said that was the only way you could make water move uphill - defying gravity - was though the capillary action of the uncompacted mound.

This was not a hugelkultur though. I'm not sure if it would work the same. The wood might break the capillary action, I don't know. I think an HK would hold water like a sponge but I'm not sure about wicking.

For your other question I don't think you want any exposed wood in an HK.

CJ --

I recall seeing that video and you are right that wasn't a HK bed. Just an uncompacted mound. The water line was like 6-8 inches above the water line. Thanks for reinforcing that. I am going to rewatch the video and see if I gather any more info from it.

A.J.

A.J. Gentry wrote:I am very happy to locate this thread as I am really trying to picture what a hugel / swale cold climate set up would look like. I was just listening to one of the podcasts -- #228. Paul and Geoff Lawton are talking swales. Size and depth. And I think they chat on / off contour (maybe not). I wrote down that Paul said 8 - 12 inch depth for the swale in a cold climate. But I don't know if that was for on contour or off... or both.

I will post my specifics --
Slope is 10 - 15 degrees from NW to SE
Average annual temperature 52.8 F
Average annual rainfall is 39.4 inches. With 27.7 inches of snow. (I admit I am not sure how to locate how much of this falls during the growing season.)
I have not put the beds in yet, but if they run N-S they would be 200'. If they run E-W they would be 60'. (E-W would be contour) These would be pretty tall. The land has a lot of rotten wood from old trees. So maybe 4-5' tall.

I guess my two main questions are (1) Does the bottom of the swale butt up against wood or soil? (I hope this makes sense or that I can explain better). Let's say I put in a swale E-W. I take my shovel and start to dig the swale at 12'' deep. Would I dig another trench (down slope) to toss the logs in then cover? OR do I dig my 12'' swale and put the wood (again down slope) on top of the soil? I was thinking in order for the wicking action of the hugel to work the water would have to have access to the decaying material. Most of my soil is clayey loam.


(2) Is there a way to both capture the water and let the cold run run downhill? These two things seems mutually exclusive to me. (Again a concept that is tough for me to visualize). If I were letting the cold air go wouldn't that mean I was off contour and therefore wouldn't be able to hold water? Should I even worry about water because of the rainfall in my area? Because of the size of the hugels and once they are in place for 2 years I won't have to worry about it anyway?

A.J.

Once upon a time I started to breach this topic with Paul and he began to pull out his podcast recording apparatus and I got stage fright and declined participation. That means a few things. One, I am partially to blame for not having more of Paul's thoughts on this topic in podcast form. Two, I still don't know what he might have said since that was the end of the discussion. And three, I feel like I should try to participate in the convo now if only to interject my best guesses.

Right away, that looks like A LOT of precipitation so I'm thinking swales aren't needed to hydrate your landscape. One of the things I've noticed in my limited experimentation is that decompaction is a major benefit to the soil when creating swales. That said, making hugels will also decompact.

While watching the Agro Rebel, I was looking hard for on/off contour stuff on Sepp's place. I noticed that there are places where hugels appear to be laying perpendicular to contour, and places with mounds that look more like lots of lumps in a pattern resembling moguls on a ski slope. There are also, of course, 72 ponds (shallow and deep) tucked all over the place that are linked more to contour. I think the major take-away is lots and lots of diversity in micro climate creation.

One of Paul's things is TEFA or Textured Earth Food All-year. He seems to purposely leave this vague. Just add lots and lots of texture. In my mind, that means something like do lots of experiments. Do lumpy stuff all over the place big and small, on and off contour, wood buried deep and wood higher up, wet and dry spots, hot and cold places, and plant all kinds of stuff and see what happens. Lots of edge. Work animal paddocks into it all somehow. It's hard to get into that patient kind of mind set but could be incredibly liberating. Do whatever the hell you want to see. You can always tweak it or do something totally different. Observe and interact.

As far as I can tell there still remain these two immutable rules lest you reap the Wheaton whirlwind :

DON'T TRAP FROST

DON'T DRY OUT YOUR HUGEL BEDS BY HAVING STICKS POKING OUT OF THEM (unless those sticks are "nails" holding down deep mulch)

Its - 10 right now, here in Hungry Horse, Montana. I have 3 Hugelkulter Beds, used for the first time last spring,,My growth was amazing. I made a new one this fall, so its marinating in the cold...I will turn most of my garden beds into Hugels.....I live close to Glacier National Park, and we are colder up here, do seem to get a lot of rain,,,not a lot of sun.....Hugelkulter is the way to go...

I love my beds, I made them fairly small but will keep adding more beds in my yard...

Oh wow, do moguls resonate with me! My land already looks much like that! I think these hillocks and depressions naturally developed partly due to the glacial rock that got left behind, but also as trees fell over, uprooting themselves and decomposing. Sepp Holzer probably noticed and took advantage of the same thing, arranging them how it suited him.

Hugelkulturs and swales are very different things, Sepp doesn't use swales but rather systems of terraces and ponds that meet his water retention goals. Hugelkulturs are used to wick water from ponds or are saturated by rain events on terraces. Sometimes he creates humus ditches that function kind of like swales, that's as close as it gets.

I have seen a couple on-contour hugel-swales built by other people, and they were quite happy with them. That said I know that this is something Sepp specifically does not recommend, for several reasons. Sepp builds his earthworks to be as stable as possible and last for generations. While visiting Austria this is the thing I was most struck by, the stability and redundancy of the earthworks he creates. Before making a pond on a steep slope he will even make a terrace first to observe if a pond is possible. For water retention on hillsides terraces and ponds are without a doubt his preferred treatment.

I have not see anything that even vaguely resembles a hugel-swale at the Krameterhof, at his new farm the Holzerhof, or during any of the workshops in North America. I can't speak for his other projects around the world, but from hearing his answer to similar questions a number of times I gather that the stability of this type of earthwork does not meet his goals. All of the terraces I saw pitch in two directions, so that they are able to withstand huge rainfall events.

The wood in Hugelkulturs breaks down over time and destabilizes the mound. This is why Sepp would not plant trees in a hugelkultur, nor use them on contour like swales. I can imagine how a couple of years into decomposition a large rainfall event could cause a section of a hugel-swale to rupture. This means you would have to come through every couple of years with a machine for repairs. Ideally Sepp likes to come through with the machine once and then never touch it again. I can definitely see how this type of machine use would not be ideal for a developing agro-forestry system.

Is there a way to both capture the water and let the cold run downhill?

I think this is the terrace and hugelkultur approach that I saw at the Krameterhof. The terrace and wood inside the mounds store the seasonal water, while the off-contour hugelbeds allow the frost to flow downhill.

Should I even worry about water because of the rainfall in my area?

This really depends on when you get your rainfall. Is it evenly distributed throughout the year or is there a dry season?

the only way you [can] make water move uphill - defying gravity - [is] though the capillary action of the uncompacted mound.

I think this hits the core of TEFA. Rough and loose, except for the dams of course. There are some soils conservation studies/strategies where they dimple the landscape; the studies have seen an increase in water and humus retention compared to the control, pretty logical. This is also one of the effects of appropriately managed mob grazing, the hoof prints form dimples for water and humus retention.

I've attached a picture of a hugelkultur we saw at the Krameterhof. It is currently a berry propagation patch for Josef, Sepp's son who now runs the farm. It is kind of hard to tell from the picture but it is located on a terrace and oriented slightly off contour so that the water slowly travels downhill all the while saturating the soil and wood.

This is a great thread, I want to offer some of my first hand experiences managing the hugels installed by Sepp at the Place of Gathering. Sorry for the Length. ENJOY!!

Below is a photo of an installation Sepp did in Montana at Place of Gathering. If you look closely you can see little reflections at the base of some of the hugelcultures. This water pooled at the base of these hugels after rains because they are placed on contour and not down slope. The slope is very gradual, maybe 5*. Plus the Hugels have curves and meanders in them which actually help to encourage pooling at the base of the hugels. During the management of these hugels I found these areas to be very valuable. The hugels adjacent to the puddles were obviously more moist and the areas where the water collected grew plants like parsley, carrot, parsnip, mallow (althea officianilis). Again, big fan of what placing them on contour achieved.

No erosion was evident in this scenario. In reference to frost drainage, the areas did seem to be a little cooler, which had its benefits in our hot temperate summers.

I believe hugel swales have there pros and cons. It would depend on how it was built. The important thing would be to build the hugel on the downslope side of the swale to have enough material so that as it broke down it wouldnt drop to a point that water could spill over and generate erosion. Building a mulched hugel swale would prevent the water from having much opportunities to move and generate small erosion gullies. By having the swale sloped down contour slightly at an angle of 1:300 or 1:400 like Yeoman did, then you could ensure the water from heavy rainfall events would flow down the swale and not over it. Also, we must consider that when the wood breaks down it turns into what is called brown cubicle rot. Brown cubicle rot is a stable conglomeration of carbon that will vary little in size once the wood has achieved that state. This is the end goal of the wood in a hugel and resembles biochar in structure and function. Due to its angular nature, it is actually quite structural... like building a house with bricks vs river rocks. In terms of "charging" a hugel with water, swales would undoubtedly be effective at this.

When I was talking to Sepp about how to manage the installation after he left he suggested we irrigate the hugels, contrary to the purported myth of no-irrigation necessary. However this suggestion was suited for our climate which averages only 16 in of rain a year. He suggested 3 soaker houses: one at the peak and one on each size slightly above half way up the hugel's side. When experimenting with this i found it took about 36 hours to saturate the whole hugel at a pressure rating of 25 psi and a flow rate of 7 gpm. Once the outermost layer of soil become dry the soil "wick" that allowed for evaporation of the water stored in the hugel was broken and that stored water would remain for up to a month.

In fresh hugels the wood will not store very much water, but it will release plenty of nutrients and host microbes. 2014 will be the 3rd year of our 6 foot tall alder, dogwood, hawthorn, cottonwood, aspen (fresh and dried) filled hugels. the first year the wood and churning of the soil released loads of nitrogen. The second year the wood locked it up. I suspect this third year we will begin to see a balancing effect where water and nutrients can be stored in the decomposing wood.

Adjacent to one of the ponds we did not actually put a hugel but simply a soil berm of fine sediments (see photo below). This is where we planted fruit trees and Sepp's Famous Rye (which did great, WE HAVE SEED!!!). The fine sediments allow for the effective capillary wicking. By planting the fruit trees here they are above the phreatic zone (the layer in the soil where water fills the spaces between soil particles) and are not drowned by the water but have the benefits of being in saturated soil. From my observations of the site, the coarser soil materials did not wick moisture as effectively (eg. the sandy hugels require more external watering). The tops of all of the hugels were constantly dry, constantly. Unirrigated generally the hugels were dry for the first 8 inches of the soil. Starting seeds in this dry soil is a waste of seeds as they would become seedlings and then could not reach the moist parts of the hugels and die. Just like with any other gardening it is important to give enough water to young plants that they can become established but little enough so that there roots reach deeper.

To respond to the dry tops I planted deep rooting perrenials such as rhubarb, horseradish, elecampane, and jeruseleum artichokes. These have the capacity to reach down deep into the hugels for moisture. They are also all divisible by root divisions. they all also feature massive amounts of leaves. These leaves provided chop and drop material, shade for the driest part of the hugel, prevented deer from crawling over the hugels, and captured dew from morning fog that would drip onto the hugels.

All of the trees planted on the hugels are doing INCREDIBLE. They were planted by mistake as Sepp told us to only plant bushes on them (2/3 up on the hugel). But now years later they are doing better than any other trees (except for those planted adjacent the ponds). It seems to me that planting trees on hugels is like how nature plants trees on fallen redwoods... I actually encourage it. From my experience what hugels need more than anything in order to minimize watering needs is mulch (leaves fallen from the trees planted on there tops), and shade. From growing vegetables throughout the installation i observed that they require much less light than commonly believed and did better in places where they were in the shelter of canopy (full for part of the day and dappled for part).

I was doing a restoration job with some friends that involved some thinning. We took the thinned trees and milled them for beams (a very valuable product) and took the slash and chowdered it up (put it in a pile and chainsawed it up to make it into finer materials). We then filled a 3 -5 foot deep trench with this slash and built hugels over the top of them. I feel that doing this on contour would provide a trench for the water to sink into beneath the hugel and would not compromise the structure of the hugel. This Hugels performed great. By having more thin branches rather than whole logs incorporated into the hugel we ensured there was a high proportion of nitrogen to carbon (as well as a higher proportion of cambium to support mycelial populations).

PlaceofGathering.com

http://www.indiegogo.com/projects/water-is-life-edible-restoration-at-place-of-gathering/x/6015170

I love that aerial photo so much, what a beautiful landscape! Wouldn't these hugelkulturs be meandering just off contour? As they form a couple of pools, rather than an even body of water like an on-contour swale? I should clarify that by off-contour for the hugelkulturs at the Krameterhof I mean just off-contour, not down-slope (I should have made that more clear). They are definitely slowing the water and spreading it out, but also letting it move. This is the same idea that Darren Doherty taught and what I saw at Ben Falk's. Moving the water ever so gently from valley to ridge. I really like the meandering at Place of Gathering, seems like the most natural.

That's great to hear that the trees on the hugels are doing so well! Some friends have been co-planting support species and fruit trees in a hugel-swales, in a really harsh climate, and they are really encouraged with the results. Have the trees in the hugelbeds at POG also been benefiting from the irrigation? I would have guessed that the trees closer to the phreatic zone would have done better. Does the water seem to wick from the phreatic zone into the woody debris?

As for A.J.'s question of building hugel-swales on a 15 degree slope with 40 inches of rainfall, if it were myself I would be cautious. It is always best to make a to scale model with the real material first and test it with a simulated intense rainfall event, this can save a lot of heartache later!

When woody resources are available using it to generate brown cubicle rot is a tremendous asset. When I see a compost operation like Karl Hammer's, making meandering windrows for composting, it looks a heck of a lot like hugelkultur. Increasing the surface area to promote air exchange and increase the rate of decomposition. In Austria Sepp even mentioned coming through after 5-10 years (climate dependent) to reshape the hugelbeds after they break down.

At the Holzerhof there was not a single Hugelkultur. I imagine that's because the woody resources weren't available, as the land was previously used to produce corn.

It's all about working with the resources that nature provides.

Ok, so I've been reading all this and I'm still not sure in my situation what to take away from it all. In the big picture I'm just not sure how permaculture earthworks applies to my flat land. I will give a very specific site though that I'd like to do something with and hopefully I can get some advice to atleast give me a place to start. I have this little hill, it's not much of a hill, most of my unforested land is very flat. So I have a high tunnel on the top where the hill flattens out and on the downslope toward the driveway I would like to put in a terrace that would catch the water coming off the high tunnel going down the hill before it got to the gully beside the driveway. The wall for this terrace will be somewhere between one and two feet high on contour. It will probably stretch back about 15 to 20 feet to where it meets the hill. I will plant a food forest on it with many types of fruiting trees, bushes, and vines. I watched a video from Jack Sirko and he mentioned combining the terrace and hugel ideas. I had been thinking of filling it partially with wood chips to make a hugel type effect but then read that they would breakdown too fast and steal too much nitrogen. So then I was thinking I would get wood from our forest where there are downed trees etc to fill it in. But now I've read that we shouldn't plant tree (according to some) in the hugel type plantings because of the wood breaking down and the whole thing sinking with that. Then I thought, of course, if I make a terrace with wood in it, it's going to get sink hole type areas and this is not going to be good! Anyone have any suggestions? By the way I'm in Massachusetts, right near the RI and CT borders. It gets cold, zone 5-6. We get a pretty good amount of rain evenly through the year. Thank you!!

Wenona
Chockalog Farm

Wenona Boucher wrote:... So I have a high tunnel on the top where the hill flattens out and on the downslope toward the driveway I would like to put in a terrace that would catch the water coming off the high tunnel going down the hill before it got to the gully beside the driveway.

Seems like you'd want to capture that runoff in a swale instead of a terrace but I might not be visualizing the property right. Swales are tree planting systems. In MA you want to plant the trees in the uncompacted soil mound below the swale.

Wenona Boucher wrote: But now I've read that we shouldn't plant tree (according to some) in the hugel type plantings because of the wood breaking down and the whole thing sinking with that. Then I thought, of course, if I make a terrace with wood in it, it's going to get sink hole type areas and this is not going to be good!

I've heard that recently too, about not planting trees in HKs. I don't think you want sink holes in a terrace but in an HK it's supposed to be OK, think of it as tilling very, very slowly, plus if you keep adding mulch, new material will fill it in.

Jesse Biggs wrote:


Once upon a time I started to breach this topic with Paul and he began to pull out his podcast recording apparatus and I got stage fright and declined participation. That means a few things. One, I am partially to blame for not having more of Paul's thoughts on this topic in podcast form. Two, I still don't know what he might have said since that was the end of the discussion. And three, I feel like I should try to participate in the convo now if only to interject my best guesses.

Since you said that I was going to try and blame you for there be no podcast in this space. (j/k) But since you jumped into the conversation now. I am grateful.

Jesse Biggs wrote:
Right away, that looks like A LOT of precipitation so I'm thinking swales aren't needed to hydrate your landscape.

Thank you for confirming this... I thought so. But it is always nice to hear someone agree with you.

Jesse Biggs wrote:
One of Paul's things is TEFA or Textured Earth Food All-year. He seems to purposely leave this vague. Just add lots and lots of texture. In my mind, that means something like do lots of experiments. Do lumpy stuff all over the place big and small, on and off contour, wood buried deep and wood higher up, wet and dry spots, hot and cold places, and plant all kinds of stuff and see what happens. Lots of edge. Work animal paddocks into it all somehow. It's hard to get into that patient kind of mind set but could be incredibly liberating. Do whatever the hell you want to see. You can always tweak it or do something totally different. Observe and interact.

All awesome stuff I will get experimenting with. Thank you so much for this thread. In all honestly, it helps me a lot.

Jesse Biggs wrote:
DON'T TRAP FROST

Clearly, I need this imprinted in a tee shirt. Or it may be my next tattoo.

Hello all. Just wanted to share some pictures of some on-contour mini-hugel-swales some friends and I have been chipping away at.. thought this would be a good place.

Our goal is to create a irrigation free/low maintenance food forest. Definitely wanted to throw some of our abundant rotten wood into the mix. The contour lines we're staked out with an A-frame level. Each mound is curved uphill on one end to direct the water into a pond built below.

We sowed trefoil, clover, lupines, yarrow and some native grasses on the mounds (lots of deer so somewhat limited) and yesterday we planted 11 fruit trees and 4 hazelnuts! (trees are caged with comfrey, lemon balm, valerian, aronia and fava beans planted around each)

Thanks for all the insights michael and zach!.. Makes sense to be cautious about planting trees in large hugel mounds (esp. bare root transplants w/o a taproot) I hadn't really thought of that...

I'm thinkin that in this situation with small hand dug hugel-swales we can get away with planting our trees directly in the mounds? My thought is that the wood would help/force the roots to spread until they eventually sink and anchor into the soil below?

Here are the finished mounds.. hadn't put the trees in yet but I'll take some more shots to share once things green up a bit, if ya'll like..

I'll throw in some dorky pond pics too..

What charming projects!

I'm in the Okanogan Highlands, north central Washington, may be a similar inland environment to the original poster's Idaho location.
A bit less rain, though - our valleys get 11 inches/yr, and we probably have a little more up here in the hills judging from the forest. That difference in rainfall might make a difference to your situation.

I'm just a year into my first hugel experiment.
I did a short bed (20 ft?) roughly on contour, on a south-facing slope in an existing fenced garden area. Slight curve to catch runoff, but areas on either side were sloped to allow any surplus to drain to a swale-like lower bed below. Hugel about 3 feet tall, layered rotten pine and horse manure and dirt. Hope was to capture snowmelt and hold the garden over longer periods between watering.

I thought frost was our limiting factor (55 to 70 days growing period, according to the folks who've lived nearby and gardened for about 10 years). So I used the sunward side with rocks, to try to make some sun-catching dishes for tomatoes. On the back (shady, uphill side) I did kinda random salad, onions, tried some herbs on both sides, potatoes on both sides where there weren't tomatoes. Tried to start tree cuttings in dirt pockets (fail) and rooting crowns of horseradish and rhubarb (looked good up through the fall, will see in spring).

The shady-side potatoes did immensely better. I now suspect that the water in summer is a bigger factor than the frost (2 months dry is sometimes an underestimate).
The frost came while we were gone; took out all the tomatoes on the front side; potatoes on the shady side, uphill side looked in better shape than the ones on the sunny, downhill side.
Radiant frost vs. moving-air frost seems like an important issue to note here. (Same side that is exposed for sun gets lots of radiant frost, heat loss to the open sky at night. Open sky in dry climates can be thought of as about 3 degrees above absolute zero; when the land gives up its heat, sky does not reciprocate.)

The frost came, hard, to our hillside at 3200 feet and the valley floor at 900-1000 feet, the same week. It does not seem like minor differences in air flow made much difference in this type of frost event. My gut is that in this climate, with our arid summers going into fall, and the first frost happening in dry air, frost is going to be more of a sudden, clear-sky, radiant frost than a mass of cold air. The value of the cool pocket during those hot, dry summers for reliable growth may outweigh the possibility of winning a few extra days due to dodging downhill flows.

But if you are in one of those steep Idaho valleys with strong valley winds, you might get a bigger dump of cold air from the plateaus than we do in our little mountain bench.
Idaho is between me and Paul in MT, and Paul is a huge advocate of not creating frost pockets. Maybe in the moister areas, you will have cold heavy damp air moving down those slopes.

My short length hugel would probably let cold air could spill downslope. Potatoes a little further down, in a swale-like pocket below the hugel, died back before the potatoes on the hugel did. Intermittent watering also a factor - they will be getting some buried logs for this year.

I'm guessing that for the higher-rainfall folks in the Midwest and New England, your humid summers mean that the above doesn't likely apply. You get some summer rain, and your frost events are more likely to involve moist air. Your summer rain sometimes comes as downpours, too. Very different climate.

Can the more experienced hugelkulturists speak to the specific water / moisture / humidity details in the seasons at those sites? Is Sepp's land more of a Mediterranean (dry summer, wet winter) cycle, or more of a humid summer with fall precipitation?

I can see the point about not using hugels for permanent water catchment. Always thought they were more like nurse logs, to get something started and then dissolve back into the soil. While I've seen trees with splayed roots in the coastal NW that clearly were straddling a nurse log before it rotted away, I don't see that here in our dry inland woods. Planting trees in dirt, near the hugels to benefit from the nurse log effect, but not in them, was the info I got. My dirt pockets apparently were not generous enough; next attempt will involve large mounds of dirt with some adjacent hugel goodness.

Because of our very dry, hot summers, and the extensive frost every other time of year (to -20 or even -30 F, which is like -25 C to -35 C), getting the moisture happening in summer seems a more critical tactic than trying to outsmart the frost giants. You can hide from the sun, but the frost giants have a very big hammer in these parts.

I'm working on shading snowpiles for meltwater irrigation, capturing and delaying the thaw, to bring meltwater timing more in line with last frost. And I need more trees, both for radiant frost protection and for light summer shade.

If I could count on being here the night that the first few frosts come, I could bust out the cloches or something. I may yet do a greenhouse, and resort to timed irrigation to get things established with more consistent water than I can provide by hand. For now, what can grow here without much care is what I need, and hugels are a season-extender to things survive my absences or neglect during those critical, hot, dry summer months.

Thanks to everyone for a great thread. Lots of good tips about things to try, things to expect.

-Erica W

Erica,

I concur on capturing water vs extending the season from frost for a few days. It seems to me that frost, when it comes, is so pervasive that you may not be able to fight it.

I live in Indiana and we just came off 2 very dry years with a perfectly wet year last year. Precip will vary year to year, so it stands to reason the nature of the frost will too. Nonetheless, most years, it seems like a rain will come in the evening, then temps will get down to 35, or 28, or thereabout. With all that cold wetness, the plants are done. This year that didn't happen until mid October when the plants were way past their prime.

Cold is cold. Granted, there may be seasons where some nights frost comes early and unexpectedly and strikes right near the frost point where a few hours of extra warmth could mean the difference...so again every season is different. It's not something I feel I can plan to avoid.

However, what is needed no matter what, and what will make your plants healthy and strong, is plenty of water.

Lastly, one minor point is that since most hugels that get built are not Sepp Holtzer height (they are rarely over 3 feet), is a frost trap even really a concern?

The comment about Sepp Holzer height made me chuckle. I do get the impression Sepp advocates, and have been told flat-out by Paul, that hugels and textures need to be bigger than mine to get the results they want.
But our landscape has some lovely existing texture, ridges and bogs around a pond, with stable groundcover, and our young soils are easily turned to 'moon-dust' by disturbance. I'm trying to work small areas, with minimal disturbance, until I get a better handle on how to pin that dirt back down in short order.
I do think that any cold air would flow around/over my little berm without much to-do, and I am looking at burying a deeper base for the next hugel to conserve moisture. This will eventually break down to a mulch-swale effect; and again, not be a monumental trap for cold air, while soaking up water with enthusiasm. Shallow frost pockets, deep water retention.

I've also used buried logs as water 'wicks,' kinda like the hessian wicks that show up in the big black designer's manual, and these seem to work even uphill. So just getting the water near the logs long enough to soak in seems sufficient - unless your soils are particularly water-repellant, making hugels entirely on contour may not be necessary. Let alone planting in the wettest spots - the whole woody base should move water from those low areas to nearby planting zones. This is one reason I like big, long, rotten logs, and try to fill in with the smaller stuff - I like to use the long fiber channels to even out the water in that base layer. We don't have a lot of rainfall, so we are moving groundwater or point-irrigation out along the whole bed this way.

George, your comments about the typical first frost in Indiana fit with my speculation about wetter climates.
In our slightly wetter spring weather, local valley orchard growers are very hyper about mitigating any unwanted frost. They use smoke, fans, flood-water, or any available heat and air controls to prevent a crop-killing frost.
Those blossom-frost events may include cold moist air coming down the hills from thawing snow or radiant-frost chilled slopes. Some of the most effective tactics involve warm moist air (formed using fans and 55 degree groundwater flooded the afternoon preceding frost) can be sufficient protection to save a crop of new-set blossoms. Smoke also provides a warm 'smokescreen' to reduce radiant frost effect, filling the orchard's immediate air space with warmer smoky air, and precipitating cloud formation or fogs if there is enough water present. It's a nasty thing to breathe (smoke is usually provided by diesel firepots, sometimes by burning green slash), but it does seem to help protect a delicate blossom set from a late frost in enough cases to warrant their continuing to do it.

Most frost pockets I've heard about are huge - existing slopes of the land, a local orchard owner was talking about why he didn't plant out the area around his pond for instance.
But maybe it takes 'huge' for people to notice the effect consistently.
I would guess a smaller frost pocket would only affect the outcome maybe 1 year in 3, or 1 year in 5. That's frequent enough for an orchard owner to notice after 8 to 10 years, but not for the average short-term gardener. (Improving your success rate by 20-30% is worth doing, but most years there will be other factors more critical to success.) Would you notice that certain trees bore a little less fruit one year in 3, and attribute that to frost vs. say more deer, or bird damage, or just the trees being weaker from saturated roots or something that might also occur in a low area?
If you have a serious frost pocket and every time you get a cold snap, those plants die and other don't, you would maybe notice sooner.

My tentative impression is that in these Western arid-summer climates, the first hard frost is most often a clear-sky event. Cloudy days, or even an early snow, does far less damage than a clear-sky frost.
Of course, the cold cloudy day followed by a clear-sky night is a cold, cold thing. (This is unusual in any given weather condition, as we more often see clouds or fog increase in the evenings, but can happen with a large enough weather front). Getting on the wrong side of a chilling cloud cover, followed by the clouds wandering off east in the evening and a chilly, clear sky, can bring on a hard frost.

I think the Midwest is more governed by large air-mass events, whereas the West has a lot of dry-sky events and valley-slope stuff going on.

A friend in a wetter coastal valley in Washington reports that they just get camped on by cold, heavy (moist) air, and even in a dry-sky frost they are going to get cold air flowing down from their hills. This year's clear, hard, cold frosts froze their kale, usually frost-hardy in that climate. She protects more tender plants with simple plastic cones, made from sheets of greenhouse plastic, about 3 to 4' around the bottom with a 6" hole in top to let hot air out in daytime, but prevent radiant frost at night.

Her 'frost pocket' is the entire valley growing region. We have a lot of valley agriculture where river irrigation is used on floodplains.
There are not that many growing areas on the "ideal" halfway-up-the-slope locations, because our slopes are so steep. We could terrace them like the Andes (those Inca did know their stuff), but haven't yet.
So here in the West, most folks either have a valley (unavoidable frost pockets), or a hilltop (radiant frost), or a forested slope. If you clear that slope, you can make a solar bowl that is vulnerable to radiant frost. If you have a sloping valley (wash, draw, holler), you could have some cold air streams funneling in that you have a choice about how to manage.

I think it would take a deep catchment in a mountain valley, in an area without enough rainfall to fill that catchment and make it a pond, where you'd be most tempted to plant in a home-made frost pocket on the uphill side of a hugel.

Can more people speak to the nature of the 'first killing frost' in their region, or whether there's a sequence of gradually worsening frosts (e.g. the delicate plants are taken out up to a month before the hardier ones).

Can more people speak to what regions they work in, where frost pocket / cold-air frost effects are clearly a limiting factor?
These may be a question for 10-year gardeners in some regions, or for teams that have continuous records of good observations. That might help others determine whether frost pockets are an important consideration for their own design situation.

-Erica W

This seems like it could be more fun with pictures.

This is a small picture of four different types of North American landscapes.

Vegetation depends a lot more on climate than landscape - so the Western picture of 'young mountains' includes both wet coastal mountains, and dry basin-and-range inland areas.
Climates change from one side to the other of the same mountain. Most of the West has long, dry summers - no substantial rains through July and August, sometimes into September.

My hypothesis is that frost pocket effects depend on the likelihood that cold, moist, heavy air will accumulate above you, and you will find yourself in the middle / downhill side of these cold air flows.

If you are on a high promontory, radiant frost is likely to dominate; your cold air is draining away downward as your land chills. You are not warmer, mind - your chilly landscape is the source of all this cold air that is making problems below.
If you are in a deep valley below substantially higher ridges/plateaus, you are in a frost pocket; not much you can do to escape. But you do have water reserves and tree potential to create localized micro-climates of warmth.
The permaculture books say to look for land halfway up the slope - but in the West, that land is often too steep for clearing-type agriculture. Can be terraced, as in the Andes. But deforestation is very dangerous on slopes; you may end up 'farming' bare rock.
In shallower sloping areas or 'lucky patches' amid steeper terrain, sub-ridges or 'benches' are ideal home locations. (Above flood/fire effects in gullies, but sheltered from wind/radiant effects by larger ridges).
Anywhere that a contour ridge across a valley would not accumulate enough water to make a pond, there's a good chance that water shortages are a bigger concern than frost pockets.

The other major land forms we have in the US and Canada are broad, shallow valleys, rounded older hills, or plains, from the Midwest through parts of New England.
(There are some mountains on the east coast, which do make important localized weather effects as in Vermont's strong gusty valley winds, but they look like hills to my Western eyes.)

The Midwest and New England enjoy a lot of humid weather and year-round precipitation from the Gulf and Great Lakes, and the occasional Atlantic hurricane. ("enjoy" may be an overstatement.)
So here I would speculate that both regional and localized air flows play a bigger role; there is not a lot of hill/valley texture dominating frost effects, and a person in the Midwest could quite easily build an earthen mound that would be the tallest feature for miles.
What's the dominant pattern here? Are frost pockets a huge issue? Are they usually localized, or will your entire property be equally subject to cold-air frost?

Then you have interplays, like the plateau-type mountains and 'hollers' of West Virginia, with the humid air patterns of the Midwest / Atlantic coast.

There is a bigger version, with my guesses as to types of frost effects, here: www.ernieanderica.info: IMG_1211-Landscapes-Frost_WEB.JPG

Thanks Erica. From my year of observation on our new property in Indiana I can say that when frost hits here it is mostly a function of solar aspect. The northern and eastern faces get cold faster and stay cold longer. The elevation change on my property might be 100 feet. When a frost happens it blankets everywhere except maybe near some forest edge and under the canopy. A few cedar trees will repel frost in deep into winter as well. It would appear, then, that the frost blanket will nab anything in a clear to semi-clear area but perhaps be buffeted by a tall stand of hardwoods or thick evergreens even if the evergreens are in the open. I think you are right on in your slope assessment. If you are mid slope, it is definitely a consideration to turn your hugels so as not to trap the frost. If you are in a flat area, it appears to me that you need be concerned more with solar aspect to keep frost away and secondarily very large components like a forest canopy and decent size slopes (at least 50 feet in steep elevation) to interact minimally with the frost to create warm pockets.

I've seen elevation be a primary factor in frost pockets in early autumn. The valley gets frost on days we don't because we're much higher up & heat rises of course. During the winter we can get snow when the valley doesn't - because it's colder up here.

See, it depends...

Sepp Holzer actually uses low areas to protect plants from frost. Huh? Let me explain :

In cold climates he has used crater gardens to protect plants from high winds and trap sun in the summer time. In the winter, the depression fills with snow, which insulates the plants. The snow in the crater garden lasts the longest, so it doesn't let the plants warm up and blossom until spring has really arrived. In the fall I guess the crater garden could capture cooler air, but it is also a sun trap, so has more heat stored in the earth and plant matter.

For season extension Sepp protects his plants from wind and places large heat-absorbing stones nearby. He also protects them from experiencing spring too early. While he doesn't state this outright, his success with this method leads me to believe that plants are more sensitive to radiant and convective heat transfer than conductive heat transfer.

In short, I think that the dangers of a frost pocket could be balanced by stones and water (thermal mass) and protecting plants from strong winds.

Karen Walk wrote:Sepp Holzer actually uses low areas to protect plants from frost. Huh? Let me explain :

In cold climates he has used crater gardens to protect plants from high winds and trap sun in the summer time. In the winter, the depression fills with snow, which insulates the plants. The snow in the crater garden lasts the longest, so it doesn't let the plants warm up and blossom until spring has really arrived. In the fall I guess the crater garden could capture cooler air, but it is also a sun trap, so has more heat stored in the earth and plant matter.

For season extension Sepp protects his plants from wind and places large heat-absorbing stones nearby. He also protects them from experiencing spring too early. While he doesn't state this outright, his success with this method leads me to believe that plants are more sensitive to radiant and convective heat transfer than conductive heat transfer.

In short, I think that the dangers of a frost pocket could be balanced by stones and water (thermal mass) and protecting plants from strong winds.

Of course he does.

Just goes to show, doesn't it? Mother nature's approach - scattering a lot more seed than is needed to replace the current plants - seems to take all this into account, as "the wrong place" gets defined by local conditions rather than guesswork.

I had a conversation with two local orchardists here at the cafe this week.
Ted (he works on big fans designed to move warm air around when a frost is near) said that he had seen it get colder in the valley in spring and winter than up top, even though in summer the hills are about 10 degrees cooler sometimes. We both live near the same elevation, 3200, but he's in a valley while I'm on a mountain bench).
He confirmed that water or smoke was used to create warm-ish air for the fans to move around to stave off spring frosts.
He understood what we were asking about contour, and remembered Skeeter locally using just low-elevation earthworks and not super-tall ones, to avoid the frost pocket thing.

He also mentioned and that bud damage was observed based on our hard Nov/Dec weather but not extensive.

I asked about how deep a landscape had to dip, for a frost pocket to form, and whether they'd noticed much difference due to elevation. Almost all our orchards are on the valley floor or the near-floor foothills; his higher valley doesn't really have them until about 800 feet lower (2600 feet) and that's not that common.

Mike responded by informing me that next years' buds are already forming on the tree while this year's fruit is ripening, so all winter has a chance to damage them.

Mike also said that he doesn't think that a pocket has to be very deep to be significant. His land has a frost pocket, where it slopes down (fine), then levels out (frost pocket), then slopes down again (fine).
Now I don't know quite what to make of that ... I wonder if orchards with their evenly-planted trees might do something different with air than other landscapes?

Maybe his flat piece just gets more radiant frost, or something.

Once again, I think a lot more walking around and observing local conditions is in order for me.

-Erica W

So to summarize:
- In most climates, sky-cover (tree canopy) helps protect from radiant frost. Where trees are not yet established, or when the trees ARE your crop, shadecloth trellises or rowcovers can help the same way.

If you have a choice of slope, or are making earthworks:
- Do you protect trees from frost by putting them on gentle slopes so frosty air won't pool around them (convective / cold-air frost),
- or by tucking them in on the sunward side of tall trees to protect them against some angles of radiant frost (solar bowl)
- or by putting them deliberately in frosty holes so that the snow will keep them insulated and keep them from budding too early?

You have to understand what type of frost is happening in your landscape, and what types of frost damage you are trying to avoid.

A tree that will be killed by an average winter cold snap is not going to be happy no matter what. Pick hardier trees. Or build them a house (solar bowl, greenhouse, etc).

If your only problem is avoiding frost-killed blossom set, that's a very specific situation.

Good local observations may be able to tell you what conditions most frequently cause that kind of damage, and which patches of existing plantations consistently escape it.
(especially in an area like this, with loads of conventional orchard growers who are very attuned to their crops. They haven't found a spray yet that 'kills' frost, though they are trying.)

-Erica

Zach Weiss wrote:

The wood in Hugelkulturs breaks down over time and destabilizes the mound. This is why Sepp would not plant trees in a hugelkultur, nor use them on contour like swales. I can imagine how a couple of years into decomposition a large rainfall event could cause a section of a hugel-swale to rupture. This means you would have to come through every couple of years with a machine for repairs. Ideally Sepp likes to come through with the machine once and then never touch it again. I can definitely see how this type of machine use would not be ideal for a developing agro-forestry system.

Many thanks, Zach, for this sensible comment.

I've been pondering some sort of hugel-swale terrace on a steep slope, and hadn't faced the facts. Thanks for helping me avoid a catastrophe!