Hugelkultur timing: when to build

I know that sheet mulching and hugelkultur mounds are best assembled in the autumn, so that they will be properly broken down by springtime for the initial planting. In the autumn when you're first putting it all together, you're supposed to seed it with nitrogen-fixing cover crops.

Here's the puzzler, though: most of the wood and brush I'll be handling when making hugelbeets will be coming from piles in my back woods. Much of it's been there for a few years now. I intend to make use of some fallen hardwood trees that have been there for a loooong time, and still haven't broken up yet. I've got plenty of brush and quasi-rotten wood to choose from. But this area is pretty infamous for yellowjacket infestations, and a few years ago when we were cleaning up after hurricane season, the yellowjackets came roaring out of their hangars in formation to defend the woodpiles. I really want to make use of this resource, but I want to wait until after the frosts come so that it's safe. And yet, if I wait until after the first few frosts to make the hugelbeets, will that mean it's too late to sow any cover crop seeds and get a decent result?

I'd think you can look at the project in two phases. Collection and laying of all the wood, and then the covering with soil and sowing when the weather is more appropriate. The soil preparation is really key, and you don't want to be digging and laying soil on top that's too dry or too wet, or else you tend to make hard work of it and damage soil structure in the process. If you're worried about nitrogen levels in the soil, and want to get planting virtually straight away, then look at chucking a layer of manure onto the wood before laying soil over that. Or just give regular fertilizer applications to the plants directly (foliar feed of seaweed, fish based liquid fertilizer, etc). I wouldn't expect too much out of the beds initially anyway, and it always pays to just leave it and let nature do its thing.

I'm not quite a year into building hugelbeets, but I have some observations:

(1) The best time is now. The sooner you have assembled all the trunks, branches, leaf mulch, grass clippings, ashes from the BBQ, biochar, and wood chips into a pile, the sooner you can pile dirt on it and plant it.

(2) It's going to sink under its own weight. You will be adding more material to it if you want it to maintain its profile.

(3) After the disruption of being moved, life will begin anew and the ecosystem of the pile will rebalance. Fungus gnats will be the first to arrive, even as you are smoothing out the dirt thrown on top. Ants and millipedes and sowbugs and other soil critters will quickly move in and get to work.

(4) The longer your growing season, the less you have to worry about things being "properly broken down". Where the ground doesn't freeze and it very rarely snows, organic matter is in all stages of decomposition, from grass cut yesterday to a stump that is several years old. If you throw it on the mound, some critter will think it is "just right" and start eating on it.

(5) This is a long-term commitment. A little investment of time in the beginning to assemble the pile will return many seasons of increased fertility for this strip of land. Instead of the the farmer method of thinking, got to plow to put in a crop, you have to replace that with the ecologist's "planned succession" method of thinking. After I lift my sweet potatoes this fall, those hugels are going to get sewn with cabbages and fava beans.

(6) If you don't like the looks of it, just hack everything down, add some more wood chips and dirt, and start over!

Sepp Holzer recommends building the hugelbeds and then sowing immediately before the soil compacts. He says that the seeds will germinate when they are ready.

So yesterday I filled in my first Hugel bed... Im ready to put my dirt back on but the thing is we have some chances for rain this week and I was thinking I should let the wood take a good soaking and get "primed" before winter. Or maybe I just finish it off... What ya think?!?

Vato Rodriguez wrote:So yesterday I filled in my first Hugel bed... Im ready to put my dirt back on but the thing is we have some chances for rain this week and I was thinking I should let the wood take a good soaking and get "primed" before winter. Or maybe I just finish it off... What ya think?!?

The wood will get soaked through the dirt. The sooner you finish it off and plant your cover crop on top, the sooner it can sprout.

I'm no long term expert myself but I agree, the time to build is when you are ready. It will begin working when you do.

I have pretty serious yellowjacket pressure here which is tricky because all the adults are allergic! Ack! I do what I can to avoid them.

If I were you if gather all my materials including soil and seeds, wait for a cold morning and go for it. If seeds would not sprout because of the cold I'd mulch it heavily and pull back the mulch in spring.

Based on our experience with building and then growing on an extensive array of hugelbeds in various configurations this year there are a few observations I would share along with why:

1. Use wet wood or build in the fall

This is to allow all winter for the beds to saturate with water. Our beds acted like a good hugel sponge all summer, pulling copious amounts of water IN to the center of the beds to saturate the rotten stumps we used as woody material as they were paper dry for the most part. For our next set of hugels we are chaining the logs/stumps down to the bottom of our irrigation pond all winter if we have to do spring construction.

**controversy warning**
2. Compact the soil and till the top

This is to ensure the bed is stable enough to be climbed on/tilled/planted and then worked all season at commercial scale while remaining fluffy enough for good root establishment and water absorbtion. The friend who built our garden is a master "dirt guy" and after extensive persuasion he convinced me that packing the beds with the bucket to stabilize them is the way to go - after seeing the results of this season I think this is definitely the way we will continue to construct our beds.

To boil his argument down:

1. Bucket packed topsoil is actually slightly *less* compacted than undisturbed topsoil - undisturbed topsoil grows plants just fine
2. Packing the beds will reduce settling and results in an extremely stable surface that can be climbed all over without much concern, including on the slopes/sides
3. Packing the beds allowed us to make the face angle much, much steeper without experiencing erosion problems and this has allowed us to plant more densely due to increased vertical spacing between plants from the steeper face angle
4.We use a hand-held weedeater with a tiller attachment to "fluff" up the top 6" or so of soil on the beds prior to planting by starting out at the bottom of the bed and pulling the tiller upwards so that we are pulling dirt towards the top as we till - this helps to control sloughing during tillage.

We also tried several beds where we packed but did not till and one that we did not pack at all.

The unpacked bed looks like a mess at the end of the season, covered in craters and sloughed soil, etc. On a commercial scale completely unpacked beds - in our experience - are not viable as they cannot take the "beating" needed to support the intensive production of annual vegetable crops and they grew food no better than our packed+fluffed beds.

The packed but un-tilled beds cannot absorb water fast enough and due to the slope most of it runs down to the base of the bed before being absorbed, especially with heavy rains - even when deeply mulched - leaving the top 2/3rds of the bed extremely dry and noticeably stunting the growth of any crop we grew on these beds. So in that sense compacting the beds without any further treatment is also not a great idea at any scale, commercial or not.

So what we end up with is 6" of tilled soil on top of the hugelbed with the rest of the material bucket packed to within 5psi of the density undisturbed natural topsoil. The "fluffy" zone provides for early root development and slows the water down to give it time to percolate into the center of the beds while the bucket packed topsoil/organic material/woody material "tootsie roll" at the center provides a highly stable "foundation" for the bed that, at least from a plants perspective, is slightly less compacted than the topsoil below where your tiller reaches in a "flat" garden. We can literally jump, climb, walk, crawl, kneel, or otherwise do whatever we want completely safely on top of these beds and they grow veggies just as well as those that were left "fluffy" to the core.

So to bring myself back full circle and actually address your question.

In the future this is how we intend to build beds and when:

1. Fall construction of bed foundation
2. Rock pick and intensive 6" deep "fluffing" with a hand held tiller
3. 3-4" of compost "piled" on top of the bed, unincorporated
4. Bed for winter with 6" or so loose straw (or other green manure) mulch and allow to accumulate water over fall/winter/spring seasons
5. Prior to planting "re-fluff" and incorporate straw & compost prior to planting


This will give us 3 full seasons for the hugelbeds to completely saturate with water prior to planting with any crops and will avoid the "dry sponge" effect our hydrometer made us aware of over this season. Also we noticed "hotspots" in our beds where plants performed differently based on "micro-soil" climates we created when building our beds and "mixing" up many different materials at varying PH and soil constituencies. Our impression is that by building 3 seasons in advance we are allowing time for natural processes to "normalize" the soil through the re-establishment of the soil food web that was disturbed during the construction process and provide a healthier environment to receive initial crops. This is also the process we intend to follow when fallowing our beds.

Anyhow we are only sharing our opinion based on the experience of a single season, albeit with a huge number of hugels in many configurations, so of course YMMV.

What does YMMV mean?

Your mileage may vary.