Friday, 29 July 2016

The Hugelkultur.

The Hugelkultur Task | Green Corridor Charity

- Alys Fowler: the joys of hugelkultur (or rotting wood to you and me) | Life and style | The Guardian
When I moved on to my plot, I inherited a leylandii trunk that was far too big to cut up by hand. It was at best something to perch on, which is exactly what I did with it until I read Sepp Holzer's Permaculture (Permanent Publications, £18.95). Here I found my solution: a raised bed that looks after itself. Powered by rotting wood, it needs no feeding or watering for years. It's called hugelkultur, and it works remarkably well.

Hugelkultur, in simple terms, is a raised bed with very steep sides. Deep at the centre of the bed is rotting wood, brush or other bulky organic material, covered with upturned turf and topsoil. The wood at the centre acts like a sponge, absorbing water and releasing heat as it breaks down. It also feeds the bed, slowly releasing nutrients. It's best if the wood is a whole trunk, because this rots slowly and steadily, rather than all at once (which is what happens if you use bark chippings).

The wood has to be buried deep, though, or you get a huge amount of nitrogen lock-up. As wood breaks down, it robs nitrogen from the soil to aid decomposition; once broken down, it releases it again, but that is some time away and nearby plants may struggle, especially if they're trying to establish themselves.

My trunk was 10ft long, a foot or so across and just beginning to rot, so perfect for the job. It was buried to where the soil changed colour and became heavier, and on top went brambles, twigs, more brush and very rough compost and autumn leaves. I also put in some nettle and comfrey tops, to help with potential nitrogen lock-up issues. I had no turf to hand, so a layer of grass clippings and then topsoil went on top.

In the first year, you need to grow plants that can cope with the bulky nature of the rotting stuff. I chose a mixture of green manure to stabilise the sides and perennials and annual veg. The first year I grew tomatoes, pumpkins, chard and wild beetroot among the green manure, Phaecelia (sown later in the summer, so as not to compete with the other crops).

Now in year two, I've established cardoons, horseradish, mint, wild beet and flat-leaf parsley along the ridge, leaving the sides for annual veg (potatoes worked surprisingly well in all that rough organic matter).

I have not watered or fed anything, and yet I harvest well. It is also rich in wildlife, acting as a giant beetle hotel. And when you dig around, you can see find strands of mycorrhizal fungi going to work on the wood. In short, it is a damned happy habitat. As the motto goes, "Feed your soil and it feeds you."
- Alys Fowler.
- Alys Fowler's gardening column | Life and style | The Guardian

How to Build a Hugelkultur Bed
Gather woody waste materials such as dead logs, extra firewood, pruned or clipped branches etc.
The wood can be either rotting or fresh, although already rotting wood is preferable because it decomposes faster.
Lay the wood in a mound about 1-2 feet /60cm high and stamp on it to break it up.
Or dig a trench to lay the wood in.
Cover the wood with other compost materials such as autumn leaves, grass clippings, garden wastes, and manure.
This stage is optional if you aren't planning to plant the bed immediately, but bear in mind that wood is high in carbon and will consume nitrogen to do the composting.
This could lock up the nitrogen and take it away from your plants (nitrogen robbery).
But well-rotted wood doesn't do this so much.
If the wood is far enough gone, it may have already taken in so much nitrogen that it is now releasing it.
Adding a nitrogen-rich component is therefore a good plan if you want to start growing right away.
The waste from end of season peas and beans would be good for this – in fact anything you might grow for green manure could be used.
Rotted manure or your own compost made from household waste will also do the job.
Cover the wood and compostibles with a few more inches of soil and/or prepared compost, and you are ready to begin using the bed.

Among the plants known to do well in hugelkultur beds are potatoes, squash, and a number of different species of berries.
Some gardeners plant the bed with cover crops for the first year to improve fertility even more before adding vegetables or other plants.
These could be alfalfa, Hungarian grazing rye, red clover, buckwheat, field beans, white mustard etc, all of which are good nitrogen fixers.
The bed will initially be quite deep, but will settle out considerably. It will probably be about 1/3 the original depth a year from making.
Then you can place rocks or wooden edging around it and rework it a little into a slightly more elegant raised bed.
In the meantime it will work really well for a goodly crop of potatoes, which, if you are starting the process at the end of summer, could be a late variety suitable for harvesting in December.
Growing potatoes as a first salvo is a really good idea.
They seem to improve soil structure, and the earthing-up and harvesting processes add even more benefits.
Earthing-up can even be done with straw, which is a popular method of growing them in Scandinavia.
It makes it easy to harvest small early crops of mew potatoes without disturbing the plants too much, and the straw acts as an insulator, adding even more warmth, and also stops weeds getting a hold in the top layer of soil.
- Hugelkultur: Using Woody Waste in Composting

-When wood/carbon rich matter breaks down it steals a lot of the local Nitrogen. This Nitrogen is needed by your plants. To counter this you can plant leguminous plants that together with bacteria near their roots fix Nitrogen and make it available. A ton of chipped wood would rot down quicker but would also use up more Nitrogen initially. A large log weighing a ton would rot down more slowly and use up Nitrogen less initially.
-After a while it will settle down and lose some shape and lose growing space.
-Can provide a habitat for animals you dont want (mice/rats).

Now you will see I put "supposedly" a few times. This is because you dont really see any proper comparisons that show the benefits of hugelkulturs against a normal raised bed. I like the logic so I am willing to give it a go; plus I can get rid of all that wood without burning it or leaving it around for a habitat. Hopefully I can show some sort of comparison between similar plants grown in a non hugel-bed.
My allotment - updates and general projects (Hugelkultur, orchard, pond, munti etc)

- Low Cost Vegetable Garden: Hugelkultur
- Wood for Food ~ Gardening with the Slow Burn of Rotting Wood

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