deep composting

Has any one ever done deep composting in your garden? What I mean by this is the ideal we have is to dig a hole 18 to 24 inches deep put In the stuff we want to compost and cover with dirt.We think this will improve the nutrients in the soil as well as bring the minerals from deeper down up to the surface and also be a place to add the new worms into the garden bed. Placing these holes in between our rows of planted vegetables is our ideal.
PLEASE give us your feedback.

I don't exactly do what you are describing because I don't have soil that deep, thus I can't hand dig an 18" deep hole. But I do something else sort of along those lines. I make what I call grow boxes out of four wood pallets wired together and lined with something to help retain moisture, such as old tarp pieces, old feed bags, sheet plastic, etc. I fill the box to the top with all sorts of organic debris -- leaves, grass clippings, weeds, garbage, manure, livestock pen litter. I stomp it down and water it as I go along filling the box, adding a shovel of soil every 6" layer or so. When it's finally full, I top it off with 3-6 inches of soil. Then I seed into that soil. Over the course of time the material will decompose, thus the soil level will go down. In 2-3 months it will normally drop a foot.

My grow boxes work great for certain crops. So far I've grown beans, peas, sweet potatoes, tomatoes, squash, gourds, and pumpkins with great success. I bet there are plenty of other things that this would be good for. I do not need to use commercial fertilizer because the decomposing "compost" provides the nutrients. When I harvest the crop I normally open the box and move the "soil" to a low spot in the main gardens. Then I start over again.

Over in Hilo I know of gardeners who use trench composting for growing taro. They dig a trench like you describe and fill it with organic material, often coffee production waste, then cover it over. Then the taro is planted between these trenches. The system works.

We tried the 4 pallet method last year not sure what we did wrong we put grass and chicken and rabbit poop in the box added a little dirt and this year all we still got in that box is grass poop and dirt we did something wrong just not sure
in our other box we built we added more dirt can't really call it soil because it was just brown dirt that was in a pile on yard that had very little growing in it so I don't think it had any nutrients in it but that box now has beautiful compost in it we are going to turn it again as we see some stuff in it that hasn't yet composted (think we added to much grass at one time) and let it compost another year and use it next year in our raised beds and buckets.
and as for as deep soil we have places in our yard where the cliche is right on the surface so we built raise beds and put buckets in those areas and have had good luck with that.
But we really want to keep our deep good soil just that deep good soil so we are trying to figure out ways to compost in place.
In some places on our property the good soil is deeper than 36 inches we would like to keep this soil well fed so that we will continue to have good groups for many years.

On your failed pallet box, I am going to guess that it dried out. Composting can produce a lot of heat, thus quickly drying out a pile. Once dry, the composting cycle stops. I had a similar problem when I first started using the pallet boxes for compost piles. I remedied the problem by making sure the pile was moist by adding water, then kept the top covered with several layers of cardboard. Plus I lined the pallet box with thick cardboard to help keep the moisture in. That worked better for me.

For my growing boxes I'm now using pieces of old feed bags and tarps to line the boxes because by growing in them, they need to last several months in a row. The cardboard decomposes too quickly.

I never thought of lining them.
In southwest new mexico every thing dries out quickly soil you water today can be dry as ash the next day.
We will try that line them with our feed bags and try it again it will help keep the wind off them and the moisture in.

Hau Debra, what you are describing is anerobic composting. This method can work but it will not really heat up and it can provide pathogens great places to thrive.

I have some spots that I bury lots of compostable material, I then mark these areas so I can come around and aerate the spots by driving a piece of 3/4" EMT conduit I have for this purpose.
By doing this I can 1) take core samples to see how things are going along and 2) introduce air to the deepest parts of the buried piles.
It is possible, using this method to heat up the ground enough that snow will not stick around where the buried pile is located.

I mostly use this method for making leaf mold, when it is done I dig it up and take it where I need it to improve soils.
The last place I owned, I had two pits that I used for 20 years, the soil around the pits was simply awesome.

Now that I have purchased my retirement farm which has bed rock under 2-4 ft. of soil, I may have to change methods for leaf mold. Since I also have a forest, all I really have to do is go rake up the leaf mold I need and wait for the next batch to be made by mother earth.

The pallet box method is great for making compost, the buried method is best for leaf mold.

Thanks everyone for your replies

Debra I have not stuck with it as a permanent solution but last winter
I decided to just put all my kitchen scraps in my garden beds. Using a
Post hole digger I dug out a hole and set the dirt aside. Then when it was
full of kitchen scraps I put he dirt back and mulched it over. Then I moved
a few feet down the bed and did it again and so forth.

It gave me a place to put the scraps. Several years ago I did this for an
extended period of time in my flower beds with no ill effects.

I am interested in doing something I would call deep in place composting as the soil on my land is pitifully shallow before hitting rock (over grazing by the previous owner + slopes + winter torrential rains = super erosion).

I will be trying to build above ground with subsoil banks creating a trough and then filling with biomass, woody fibrous things and canas (hollow for air release over time), with soil layered with straw and possible manure then a thinnish compost cover in order to allow for good water filtration from the beginning. But I feel very uncertain. Thoughts?

I have started moving to sunken compost beds / huglekulture as a way to get deep pits of organic matter and clear brush and compost piles to cut the hiding areas close to the garden
so far I got one 50 x 5 foot one done Thanks to a friend with a dozer . If I could not get that done I would try deep mulch or trench composting to create an oasis of organic matter I am on my first year and planting has not started I am looking at this as a long term project .

Sue

Has any one ever done deep composting in your garden? What I mean by this is the ideal we have is to dig a hole 18 to 24 inches deep put In the stuff we want to compost and cover with dirt.We think this will improve the nutrients in the soil as well as bring the minerals from deeper down up to the surface and also be a place to add the new worms into the garden bed.

This is exactly what I do, but not in the pathways. I compost directly in the beds where I want the nutrients and bacterial love, either in-between plantings in poor soil or to create new beds. Avocados and egg shells are more trouble than they are worth, but everything else decomposes nicely, including fish scraps. If I don't get 10"-12" of dirt over the top (wood chips don't count) the critters have take-out. The results have always exceeded my expectations.

Freyja Williams wrote:I am interested in doing something I would call deep in place composting as the soil on my land is pitifully shallow before hitting rock (over grazing by the previous owner + slopes + winter torrential rains = super erosion).

I will be trying to build above ground with subsoil banks creating a trough and then filling with biomass, woody fibrous things and canas (hollow for air release over time), with soil layered with straw and possible manure then a thinnish compost cover in order to allow for good water filtration from the beginning. But I feel very uncertain. Thoughts?

If is too rocky to put in Swales you can do the same thing by piling
rocks and/or wood on contour and then adding your biomass on the
downhill side. In that way it is kept in place. I have done this successfully
on a rocky, sloping piece of ground.

In a study I read, they used 2³ foot manure pits to plant Napier grass. The farms planted in that way produced twice as much on average

"If is too rocky to put in Swales you can do the same thing by piling
rocks and/or wood on contour and then adding your biomass on the
downhill side. In that way it is kept in place. I have done this successfully
on a rocky, sloping piece of ground."

Thanks, this is encouraging, although I'm not sure I understand putting the biomass on the downhill side. Surely the rocks or wood would hold the biomass in place if the biomass was on the uphill side of the rocks/wood? Am I imagining this wrong? or perhaps misunderstanding the terms incorrectly.

I had originally imagined something like building a 1 meter(ish) wall/barrier type thing then filling it, making it level in order to create a level terrace composed of biomass that would become topsoil, and planting it up with herbaceous nitrogen fixers and Italian alder.

Also, does anyone have any thoughts on what sorts of mixtures of biomass would make for good in-place deep composting? Or is it more a matter of "don't worry - make it wet and airy and it'll be just fine"?

making terraces is a great way to build gardens on slopes where you can not use swales and berms.

I have a fairly steep slope on my south face, I have started putting in swales and then berms filled with rotting wood at the bottom (just above the road in) of this south face. Up near the house I will be terracing with rock walls, the areas that will become the terraces will be up hill from the rock walls and receive plenty of green and brown material along with some manures. I expect these terraces to take around two years to be fully developed. while they are composting, I am going to be planting them with clovers, buckwheat, peas and other nitrogen fixers. These will be chopped and dropped a few times each growing season to help build organic material to fill the terraces. The bottom of each terrace will have a layer of rotting wood (I have plenty of it from last years tornado to use up) then on this base, I will layer in the composting materials, water and repeat until each terrace is level before I spread the seeds.