Permasculpture – an experiment in vegetable stacking and diversity

Tim Green
Friday, 11th November 2011

Most of us mix up our veg up with flowers and favour companion planting but have you thought of growing edibles in a vertical gardening and adding a crop of mushrooms below? Tim Green shares his techniques and the results of his experiments.

Progress on the grand venture of turning the farm into beautiful, sustainable agro-ecological paradise has been particularly slow of late. It's been the usual stumbling block of the 'Old Boys' unwillingness to accept change or relinquish any control. The basic pattern is always the same; we say something like "Hey, we've been doing some research and think it would be worth trying this in some of the lower meadows."

The response is usually, "Well, I heard about someone who once tried something different in 1934 and it didn't work so it's a waste of time.....oh, and can you fix our herbicide sprayer this afternoon?"

Consequently I've found myself experimenting more and more in the tiny confines of our garden – or citadel of sanity as I like to think of it. This is a little report on one of my dabblings this year that some of you may find interesting.

I light-heartedly refer to this as 'permasculpture' because it involved making a three dimensional frame out of hazel sticks but really it is an experiment in stacking, seeing how many things I could grow productively in a small area. The starting point was a lily pad shaped raised bed, which on the surface looks quite unremarkable but, being a 'hugelbeet', has hidden depths.

Growing field mushrooms

In attempting to grow a multitude of species in a small area it was obvious I would have to use the vertical dimension and this meant moving both above the surface of the bed and below it. I started at the bottom with about a foot of fairly rotted manure full of field mushroom grain spawn. I've had good results growing field mushrooms like this before but usually cover the manure with turf so... who knows??

Planting companions: Carrots and onions together

On top of the manure/mushroom layer went a mixture of topsoil and homemade compost into which I transplanted onions (grown from seed) and sowed carrot seed amongst them. The onions and carrots were only on the southern edge of the bed, as I knew everywhere else would become shaded as the higher layers grew.

While the onions settled in and the carrots germinated I constructed the rather rustic hazel framework. It has two levels; the high point in the centre was intended for mange-tout peas/ French beans and the main structure for squashes.

After a few weeks the onions and carrots were ready for a bit of heavy mulching. I thought I'd try and grow something else in the mulch layer and decided on elm oyster mushrooms partly because they have been shown to be a great companion fungus to vegetables but also because they taste fantastic. I had some elm oyster dowel spawn (from the fantastic Ann Miller's Speciality Mushrooms) left over from another experiment so went about inoculating a load of freshly cut alder loggettes (that's just a mini log by the way).

The inoculated loggies were scattered across the soil surface and then swamped in a mixed mulch of whatever I had, which this time was bracken, straw and grass cuttings fro next door's lawn. Next it was time for the aerial plants, the peas, French beans and squashes. The peas were a favourite of mine; giant mange-touts, which originally came from realseeds and the squashes, were a mixture of a proper buttercup squash and an F1 butternut. I really don't like F1 hybrids but someone gave me a packet of seed so I thought I'd run them alongside an heirloom variety to see how seductive that hybrid vigour really is.

Keeping the fungus theme going on this one, I treated all the squashes and pea plants with a mycorrhizal root innoculant powder (from a wonderfully progressive bio-tech company called Symbio). I've had some fantastic results using mycorrhizae in other veg experiments so, in the spirit of 'try everything', into the mix they went.

With everything in place and ready to explode into action we had a three-month drought. I resisted the temptation of watering as this was meant to be a real world field test and irrigation is something that is usually beyond our water-impoverished means on the farm.

The results

So, what happened? Well, some successes and some failures. Both the edible mushroom species were the obvious losers this year. Although there were some good signs of mycelium colonising the manure and logs, I think the excessively dry conditions hit them pretty hard. Slugs demolished the French beans before they could get going and the peas produced well at first but then got swamped by the rampant squashes. The squashes just kept producing but interestingly the F1 hybrid plants only made foliage and the heirlooms made all the food. I calculated that if the squashes were grown across the floor as usual they would have taken up about 8 times the ground area in the garden and beneath all the squash mayhem the onions and carrots also provided a surprisingly good crop.

Stacking encourages resilience

I think the main lesson to be learned from the mixed results is that mixed results should be expected and are no bad thing. The whole point as I see it of stacking different species together is to maximize the chances of getting a good harvest from at least something in our increasingly unpredictable growing conditions. If I ran the exact same experiment again next year and we had a cool wet spring/early summer, the odds would shift in favour of the mushrooms and away from the squashes... possibly?

This lesson in stacking and produce diversity desperately needs to be applied to the farm as a whole. At the moment, our farm is almost entirely reliant on two products, beef and lamb. It only takes something like the foot and mouth outbreak of 2001, or even our drastically reduced hay yield last year to realise we have all of our eggs in one basket. In fact, looking at most farms in the UK today it's hard to believe that the 'eggs in one basket' wisdom originally came from farming folk. We've come a long, long way in the wrong direction. 

Tim Green is a filmmaker and gardener. He made the BBC2 permaculture classic, A Farm For The Future, with his partner, Rebecca Hosking, and now lives on the Devon farm in question where they are testing out many of the ideas featured in the film (when the 'Old Boys' let them!). They write regular features for Permaculture Magazine - Click HERE.