Notes from Forest Gardening Course: Part II

4.30am. It’s too cold to sleep. I’m scrunched up in my sleeping bag, hood over my head, wrapped in a blanket, in my long johns. But it’s not enough and although I’m not shivering, I feel the cold sinking into my bones. I made an excellent decision to get up, have a hot shower and two cups of tea. Now I’m much better for it, and I’m able to enjoy the sunrise while typing up some notes from yesterday. Leftover soup for breakfast and cookies. They were a great buy.


Making a nutrient budget

The first topic this morning was soil fertility and we covered the roles and sources of nitrogen, potassium, phosphorus, calcium and soil pH. Something new to me was the concept of making budgets for nitrogen and potassium. This is a technique to estimate how much your shrubs and trees will need, and then make sure this balances against your sources. It’s a little rough but makes a lot of sense. Since the course, I’ve taken the data Martin Crawford supplied and turned it into a nifty nutrient budget calculator. It’s geeky and fun and you can grab it here.

A young forest garden

Later on we visited a 12 acre site that Martin has been working on for around three years. It was both helpful and comforting for us to see an unestablished forest garden, as we could get a sense for what things look like in the early years. This site has a north facing slope (not ideal) and has a fair amount of exposure to wind. The first priorities for Martin were establishing fencing to protect the young plants from rabbits and deer. The fencing also acts as a windbreak and there is sections where it’s installed just for this purpose. As a rough guide, 1km of fencing like this costs £4k.


fencing 2

Natural windbreaks included rows of Autumn Olive (Elaeagnus umbellata) and Sea Buckthorn (Hippophae rhamnoides). Both bushy, perennial, nitrogen fixing plants that produce lots of excellent edible berries. The Sea Buckthorn is quite thorny and Martin’s tip for harvesting was take off the whole branch bearing berries – put them in the freezer for a few hours, once frozen they will happily fall off the branch. The only sacrifice is that the plant will not bear fruits the following season. Not so much a problem if you have several plants and then you can rotate your harvesting.

Row of Sea Buckthorn

Broom was being used as nurse trees for pioneer species, helping aid the establishment of these species. Root Grow was recommended to help draw beneficial fungi into the soil in the early stages, rather than wait for it to find it’s way from hedgerow that was situated far away in this instance.


The furthest section of the forest garden, away from the nursery was a coppicing area that included a range of trees including walnut, chestnut, Californian Redwood and other redwoods. This will work on an 8 year rotation and trees were spaced at a distance of about 2-3 meters.


The irrigation system is worth noting. Rainwater is being collected from all the polytunnels into a storage pond and then pumped using an electric pump to the highest point of the field (about 40m head). From here it is filtered and can gravity feed the site as required.

When using water for irrigation it should be clean to prevent any problems of blockages. The solar powered filter system forced water upwards, opposite to what you might expect for a filter. This was very clever as it reduces significantly the need for cleaning over the years. To clean it, you just switch the pump off and any gunk just drops to the bottom with the big rocks. If it was the other way around, you would physically have to remove the layers in the filter to clean them.

Here’s a rough diagram of the irrigation system:




On the final part of our tour we learnt about the running of the tree nursery operations, which grows approximately 4,000 trees per year.


Mushrooms, Climbers, Grafting, Tools and Path Management

For the remainder of the day, we covered an assortment of topics. My favourite session was on mushroom cultivation which I am now keen to try at our farm. Martin mostly grows shiitake mushrooms on oak logs.

We also looked at some tools. One popular with the group was the fruit and nut harvester – no more bending over – this just rolls over your apples and nuts and picks them right up. Various different sizes are used depending on your fruit/nut size.