Where does a Hugel get moisture from in a dry climate?

I've listened to Paul and others preach about how glorious Hugels are in dry cold climates. That's exactly where I live and am contemplating building a Hugel 7 feet by digging 3 feet down beside it exactly like Paul describes.

What I'm mentally wrestling with is where exactly does the moisture come from? A lot of our moisture comes from snow melt and if there is a trench 3 feet below the first layer of wood how can that snowmelt be utilized?

I'm concerned that it will become a bone dry berm without irrigation, especially in the windy area I live in.

What do you mean by dry? Can you describe it more? How many months between rainfall?

Do you have a wet season?

Do you have heavy dew season?

An average year is 3-5 inches May-June, next to nothing July-Aug, and 3-5 inches Sept-Oct.

Snow is hard to measure as it depends where it drifts up 100feet apart can have 3 inches of snow where grass catches it, then 4 feet where it drifts up.

That sounds like a nice climate for a hugel.  

I don't have first hand expierence in that kind of climate, so I'll share some of my observations and ideas and hope you can take what's useful for you and ignore the rest.  You know your climate best.  


Our dry season is from the first of may (or before) through the middle of october (last possible frost to first possible frost).  Dry season means zero rainfall and wet season doesn't get much.  If it wasn't for intermittent wet wet seasons, we would be classified a desert.  We've only done a few smaller experiments so far, but are working on a larger one.  

The raised ones tend to dry out after four or five months of zero rain.  If they can get a shower in there, it's much better.  Once they dry all the way through, it takes a lot of extra rain to moisten the soil.  (about the amount of rain that would reach four inches into the regular soil - which is about new years on our farm).  To reduce this, we found a combination of spunky, fresh, and dry logs helps a lot.   We also semi-submerged our big experiment as this seems to reduce drying.

Although this early experiment of a raised version did well with very little irrigation.  But it did need some.  https://permies.com/t/68883/permaculture/keyhole-garden-summer-drought

The other thing we found most helpful is to start building just before the rainy season and add to it until just before summer starts and cover it up.  This extra moisture in the building phase seems give it a better start and need less attention later.  

I don't have first hand expierence with snow melt, but I think it adds ground moisture which sounds useful.  

The extra wind and two months of no rain, seems like a good time to add mulch just before it starts to help keep the moisture in.  

It is my understanding that the moisture comes from the wood retaining moisture.

Ben said `The basic answer to your question is that water surface tension (ie a straw) will wick water from the wood into the soil and via microbes like fungi into the roots and up to leaves, all powered by the vacuum created as the plants’ leaves evapo-transpire water during photosynthesis.

https://permies.com/t/159826/water-hugelkultur

I live in a hot dry climate. I was sold on hugelkultur. I built one, and couldn't wait for it to "work" I finished it in August, so I planted pumpkins, and watered like all my other gardens.
I won't bore you with all my struggles with chickens doing their darnedest to level it multiple times, sliding sides, and ultimately gophers. I wanted it to work so bad, and it just didn't. It definitely could be my fault, maybe I did something wrong, or missed a step? But I also think we just don't get enough water for the logs to soak up. I always had to water, and the steep slope made that challenging.  About 4 years after building it we removed it. It made me sad.  I really wanted it to work.  If I had it to do over again I would make sort of stairs instead of a slope. I think with flat levels the water would have gone into the hugel instead of down the sides. This was my next plan when I realized it had gophers. At that point I gave up.  I do think a hugel is doable in a hot dry climate, I just think it requires a little innovation, extra water, and a longer time to get going.  Good luck.

I struggle with the same thinking.  If a flat piece of ground gets 10" of rain a summer, and you put a steep tall hugel on it, it gets the same amount of rain.  Some of it probably runs down the sides to make the bottom more damp than otherwise but the bulk of the hugel would end up drier.  Assuming you aren't wicking water up from a very shallow water table...

Plus you have maybe twice the surface area to evaporate water away from.  The ones I've seen in a cold Montana-like climate only thrive when they're watered every day or two all summer long.

For the style with 3' trenches on either side, the below ground trenchy parts seem to stay greener.  Partially due to the added run-off and because they're shaded, cool and earth-sheltered instead of hot and dry.

I live on deep glacial till. We get a lot of winter water in the form of snow, but when the ground finally thaws around the end of April, that all just vanishes into the water table instead of hanging around in the soil. I've done small hugel beds and experimental mounds, but my first at-scale mound is a slow-burn project. My hope is that the winter will charge the hugel which can then portion out the water as needed by the roots all summer. I'm not so worried about what the 10" of summer rain does as I am the four feet of snow.

In that case, I'd wonder if the hugel is frozen or thawed when the snow starts to melt.  If frozen (like my sloping back yard), that snow melt just runs downhill.

Yeah, that's a good point. During the snow-melt is the only time we have puddles on our property because the (still frozen) ground won't take it away. If the mound acts the same way, it'll just shed the water and never get it back. On the other hand, maybe the south face of an E-W oriented mound will heat up much earlier than the flat(ish) ground and be ready for ingesting the water earlier. I guess I have to get the hugel finished and then see how it performs.

I made one 5 6 feet under filled it with wood to the level of the field and build a raised bed on it. Never did what it was supposed to do. It got very dry. And i don't even live in a dry or hot climate. I didn't believe in permaculture for a couple of years after that.
Then i thought i must have done it wrong, i'll do it better , build them up on the field. Something like 90 feet long. And put cow manure on top. Nada. Rat's houses.
I'm still hoping to see beautiful pictures of hugelcultures one day.

They do need to be at least half dirt, half wood.  My understanding is that it shouldn't be a pile of wood with a cap of dirt.  The dirt should be around each piece of wood.  Layer of wood that isn't touching log to log, layer of dirt, repeat.

I'm sure i haven't done a perfect job , but basicly i packed it all in. Really nice rotten pear tree, perfect spungy stuff. I've heard quite some people complain about hugels not working over the years though. And since they're a ton of work and consensus seems to be they don't work everywhere, my advice would be, build a small one to see if it works first.
I'm growing peach trees there now they lay on contour, they've gone down as the wood rotted. Still hope to use it one day if it were only for beans to climb in the trees.