Two years ago we decided to experiment with Hugelkutur, a form of raised garden beds using rotting timber to create a mound of organic matter, air pockets and soil life.
We need to create growing areas that require minimal water as we have very long dry summers.
- We have an abundance of fallen timber that needs to be dealt with and in our region with it’s Mediterranean climate, fallen timber and branches means fire hazard and we would much prefer to be sinking excess carbon into the soil than burning it into the atmosphere.
- We need to build up soil life in our garden.
We used predominately eucalyptus and chose anything from small sticks to branches or small logs of about 15cm diameter. We did choose wood that had been fallen for a while and had started decomposing , this also meant we got some great fungal activity for free.
We made our Hugelkultur bed in winter while everything was quite wet, it is important to activate the soil life, so if your material is dry it would be advisable to soak it or water it down well as you go.
How we built the Hugelkultur Bed…
We started by digging a shallow ditch (around 30 cm deep) and placing the soil to the side.
Then filling the ditch with wood, green material, seaweed and worm castings.
When the pile had grown to about 60cm above ground the soil (and some compost )went back over the top.
The whole bed was mulched with straw and we threw broad bean seed in as a green manure crop (it was winter so broad beans were an easy option to get activity happening.
As weather warmed up enough to get summer veg in we planted with zucchini, melon’s and pumpkins.
Here’s where the interesting stuff started to happen. At first these plants were slow, and given it was in an area of the garden that doesn’t have any irrigation we wondered if the exercise was going to work at all. Once the plants got their roots down deep enough to be in contact with the rotting timber they really started to grow and required no water.
Given the success of the first bed we couldn’t help but moving onto bigger and better and created a new bed in our netted orchard area.
One small change we made with the new bed is that we didn’t make the mound as high as we felt that the wind factor on the first bed did have an impact on plant health.
The hugelkultur bed grew one of the most fantastic crop of beetroot I have ever known and now (about to enter it’s third year) is producing abundant sweet potatoes. We also had a great tomato crop.
A few hints…
The beds do shrink over time so it is not advisable to create them where you want a permanent mound (like a swale).
Large gaps and holes can appear where timber has completely rotted, creating good hideouts for reptiles.
Plant crops that can get their root down deep enough to access the nutrients in the rotting timbers
You may need to add extra nitrogen if there is a large amount of carbon to break down as the nitrogen will go to carbon break down instead of feeding your veg.
Be aware of building too high as wind can dry out the bed a lot.
While this is a great method to sink carbon and build soil it is not a quick and easy answer, we were very grateful for our amazingly enthusiastic WWOOFers that were staying with us as there is considerable heavy work involved.
Do not use any timbers that have been treated with chemicals and check on the many Hugelkultur blogs/discussions if you are concerned about the timber choice you are using.
Many people advise keeping Hugelkultur beds a good few metres away from any timber structures to avoid termite damage.
To finish with …here’s a couple of photos I took yesterday at our 3 year old bed…
If time permits we will be building more in the coming season.
If you would like to learn more about our gardens please contact us for a farm tour, come along to a Thursday lunch and explore the gardens or Join us for an Weekend Introduction to Permaculture or even better a two week live in Permaculture Design Certificate