Turn around time on soil building -- how long to build dark soil on hugelculture mounds?

Recently at my place I made a few small hugelculture mounds to see how well they would work for water retention here in central Texas. I piled up a lot of rotten oak and covered it with a pretty sandy fill I got from a landscaping supplier. Over all in size id say its about 8 cu. yards. Two winding mounds about 2 feet off the ground. After a few months in the spring I realized that I needed mulch as I was having some erosion problems and issues keeping sown seeds in the soil. To remedy this I cut a fair amount of grass and have been keeping it a few inches thick on top since. This immediately helped with being able to sow seeds and keep moisture in, a few plants that were on their last legs are looking healthy and green again! My question for more experienced growers is, how many years am I looking at to see more of a dark soil begin to form? Another one is, can I layer compost on top of this and then more grass on to that? Or would that cause suffocation problems?

Thanks!

Something geoff lawton does with heavy heavy mulch is something that might work for you . He pulls a shovel full out and puts a shovel of compost in, then plants into the compost. This should start creating pockets that hold moisture. The more pockets, the better off. This might be better than a broad layer cause you are getting some depth out of it.

The sand is concerning if its sand. Come september i would broadcast some winter grasses (annual rye, oats, wheat, clover, brassicas). Around here its sold as deer food plot mixes at places like tractor supply or the local feed store. That should get you roots to hold things together until spring. I am not sure what can be planted now, but mulch should be working.  Lab lab and cowpeas maybe? Sweet potatos?

That sounds like a good idea what he does. I imagine those pockets of compost and mulch would really help to incubate more fungus and critters to help spread and improve the soil. The sand content may be a problem, but I dont know if there are things that work to dissolve sand over time or if thats a hundred year process. its a fine sand, nothing like a beach sand. it was labeled as sandy loam mix, but stuffs been growing in it fine so im pretty happy. Id plant some winter rye in september down here but ill be leaving soon, some of the fields I work on our winter rye lasted until May! its a tough grass.

I've had zero success with low hugelkultur in my part of Central Texas.  They dried out completely.  I've had better success with buried wood beds.  https://permies.com/t/52077/Buried-Wood-Beds

For your mounds, I would put a lot of mulch on and do as wayne suggests, planting in pockets of improved soil.

hau A. Flan,

True sandy soil has no clay (what should be thought of as soil glue) and without some clay mixed in with the sand, water will sink right though, leaching all the organic goodness deeper into the soil and it will take the microbiome organisms with it.
If your soil has no clay in it, you would do well to add some (it doesn't take much, about 3% will suffice) so the organic matter (mulch) that you add will have the ability to stick around and do all the good it is capable of doing.

Geoff does his compost hole planting because he is using really deep mulch (12 inches or more) and that doesn't give enough nutrients or fairly tight structure for root holding ability for the plants. Planting in compost placed within a hole in the really deep mulch provides those two things missing in straight mulch.

Hugels need plants growing on them from the time of completion until they sink back to the soil level (if allowed to progress with no further intervention).
For adding organic matter, many of the cover crop plants, in a blend will provide a great quantity of roots, organic matter (chop and drop mulch) and nitrogen fixing bacteria nodules to any soil.
A good blend might contain some or all of the following; buckwheat, hairy vetch, all of the clovers (red, crimson, yellow (sweet), Dutch or New Zealand white, alfalfa (Lucerne), seven top turnip, rape, cereal rye, barley, oats, and just about any other plant you are willing to grow just to cut down a couple of times in the season.
The only plant I don't recommend for such plantings is Comfrey, it is far to vigorous for using for chop and drop on a hugel.

Where I live it is the hot season (not so dry this year) and I still have most of my annual winter rye growing well. (this is because of all the rain we are experiencing this year)

Please keep us up to date on your progress and remember, if you come up with a question, we all love to try and be of help.

Redhawk

I’ve been experimenting with hugelkulture in Northern California for nearly five years now, though with a very different climate and soil to yours. Poor soil that’s too high in either clay or sand alike seems to take 2-3 years to really look great, but it gets there. This is basically what Paul said in his old hugel article. You can speed it up with beneficial mulches and compost top dressing. The first year really seems to perform about as well as the soil you are putting on the wood would have anyway, but with improved drainage for anything on the clay side and moisture retention if it’s sandy. It’s key to check for holes and wood sticking out the first couple years and have some soil or compost to remedy these asap or it will wick out a lot of moisture. On the other hand, here where we can have winters with 100”+ of rain, that dynamic can be used to get a month earlier growing season when other gardeners are looking at muck. Once it gets dry enough to plant in the spring, I cover holes and sticks that have appeared from settling.

I also agree about going down in dryer and more extreme temperature climates, and going up in wetter more temperate climes like mine. Nature does this with its carbon and life, just look at the deep rooted soils of the grassy plains and the shallow soil of the forested temperate west coast.

Tyler Ludens wrote:I've had zero success with low hugelkultur in my part of Central Texas.  They dried out completely.  I've had better success with buried wood beds.  https://permies.com/t/52077/Buried-Wood-Beds

For your mounds, I would put a lot of mulch on and do as wayne suggests, planting in pockets of improved soil.

Mine have gotten pretty dry now even in this wet summer were having. I was recently thinking about soaking the wood underneath with lots of water to simulate a rain, that could help. Im not so sure right now, everything was fine without water until this last few weeks.

I was reading the articles about burying wood in sandy soil; would lining the pit with grass like they do in India help?  They take fresh cut grass and pack it 8 inches deep, around the hole they want to retain water.  As the grass goes to slim it becomes water proof.  Then you could lay the wood in and cover with compost and mulch.  Would planting a nitro fixer like clover help to start the decomposition prosses?  

This thread is so salient to me right now. I'm redesigning my three garden plots using low hugel mounds. I'm somewhere between a zone 4b and 3b, depending on how you look at the map and think about elevation and North facing slopes. Last summer we experienced a drought and I had my household hauling water, taking bucket baths, and only doing laundry in town. This summer it's July 23 and our spring is still running over! I'm only sitting here writing now because of the beautiful rain that's falling on my new hugel beds.

I found the same trouble that A Flan mentions about trying to germinate seeds on my new hugel beds. The beds dried out much faster than I am used to on the un-mounded ground. Three solutions I found so far are:

1. planting a nurse crop. I used Buckwheat to nurse along some Laurentian Rutabaga seeds. We ate the Buckwheat sprouts as the Rutabagas came up and now we're eating the last thinnings of the Rutabagas. That might turn out to be successful. The Rutabaga crop looks healthy, anyway. I have been adding "transplant mix:" a mix of leaf mold, horse manure, garden soil, sand and ash around the base of the most promising plants.

2. mulch--both cut grass/hay and chop and drop mulching. Gradually, I'm seeing some improvement.

3. I also used something like what somebody mentioned Goeff Lawton does--little wells of compost into which I transplanted starts and seeds.

Of course, I don't really know yet how any of this will turn out, but it's a great deal of fun.

My plan is to build the soil in this manner this season and gradually build it up over the rotting wood/brush/leaves that makes up the mounds. At any rate, it's clear that I'm capturing the darn lot of water that's falling out of the sky and I don't need any sort of hauling to happen this season.

I just ran across a seedball comment on another forum. I wonder if anybody has comments about using seedballs in hugels that are already planted with some kind of cover crop. For instance, I want to grow a lot of beets as a fall crop, but I'm not quite sure how to get them germinated in place without the hugel ground drying out...

thanks for the great conversation!