As a permaculture Land Centre we need to demonstrate permaculture techniques. One we are trialling are the growing mounds. We’ll observe and record their progress and hopefully we’ll be able to share our expertise and experience with others over time.
Hugel kultur or mound culture. Hugels are a growing mound, once known as the ‘german mound‘. It’s not a new technique, but one useful to us at the garden where all growing is above ground. We have four large mounds (approx 8m x 2m).
How they are made. Logs form the centre of the mound, plus brash and smaller twigs, rammed in with soil and covered with up turned turf. Another 20-30cm of soil then went over the top. So far, so good….. Much of the soil at the top of the mounds has slumped down the sides, leaving the back of the turf showing at the top. We sowed a mix of wild flower seed and red and white clover to act as a matrix planting and stabilise the soil, which it’s done successfully lower down the mounds. I think in time as the logs rot down, the mounds will lower and the soil will distribute more evenly.
How do they work? The principle behind hugel kulture is inspired by the qualities of woodland soil. Rotten wood holds moisture like a sponge, right where the roots need it. Whilst rotting, some heat is released as well as nutrients. Any fungi resident in the wood will fruit, their mycelia helping to create a good soil structure, all in all creating a wonderful, healthy growing environment. hugel detail
What not to do….. Add the timber from live willow or poplar, very resinous wood e.g. cedars, spruce or pine, especially if fresh.
Year 1. The mounds were constructed and sown with the seed matrix. Any available annuals were planted and we had an incredible harvest of chard!
Year 2. We’ve begun to plant small trees – apricot / quince / almond / hazel), perennials such as rhubarb, jerusalem artichoke and artichokes, asparagus and soft fruit – goji, redcurrant, blackcurrant / jostaberry / raspberry / strawberry / wineberry etc. One of the mounds is dedicated to herbs, medicinal and culinary and dye plants. We’ve had to make little retaining walls to make sure plants stay mulched and watered.
As the season goes on we’ll plant potatoes, squash, different leafy greens, beets, edible wild plants such as chicory, korean mint and savoury.
June hugel mound, looking good…
Lower end of hugel mounds where slope is less inclined has covered well with lush herbaceous vegetation including rhubarb, clovers, hollyhock.
Upper part of mounds remained very bare all summer, with not enough soil depth for anything other than the toughest weeds to survive. Holes appeared under logs which became popular with wasps for nesting.
There is a clear need to add organic matter to the soil which will help roots establish to form a healthy mat, holding our soil together.
Woven retaining walls will hopefully hold a sheet mulch in place over winter and into next year until central logs rot down more and even out mound profile. We are using buddleia trimmed from site.
The sheet mulch will be used to increase organic matter in the mounds and protect whats left on the tops.