Green manure vs brown manure on the allotment

Andy Waterman
Saturday, 1st February 1997

Andy Waterman shares his experiences of turning a solid clay soil into a friable tilth

A few years ago, I took over an abandoned allotment thick with couch, bindweed, dips, mounds, scrap metal... you name it! I chose it for its position - easy access, near a tap and with a short cut through the cemetery - and its shed. The allotment was to supplement my home garden, but as soon as I threw a fork at the ground and watched it alarmingly bounce back, I began to have second thoughts. Should I contact the local brick company or begin a learning curve that was as sharp as the pain in my back?

I spent hundreds of hours breaking up and hand-picking bits of root - at night I used to dream about it - but I never got rid of it all and it was beginning to get the better of me. Then I discovered free carpets at the dump and covered as much of the plot as I could - more to hide the thought of all the work than to contain the couch! After that I concentrated on what I could manage. Two years later I got around to those parts 'swept under the carpet' and found clear friable soil with just a few bits of bindweed left. Time and nature had done their work.

Associated worries

Things did not always run smoothly, however. A problem familiar to many of us arose between the Allotment Association and my multi-coloured, untidy plot with lumps of wood and old car tyres (frogs love them!). Through explanation and gentle persuasion I was begrudgingly given leave to continue, though accompanied by murmuring and rumblings.

Every year, I bought a trailer load of rotted cow manure which I used mainly for the potato patch. I have experimented with putting the manure on the surface - true no dig gardening - but this resulted in a drop in yield of well over 50%. Most of this was due to the plants dying off before maturity due to lack of moisture at the roots because the ground is solid clay.

When manuring the spud patch I now dig a trench to plant the seed potatoes in, fill it with manure and place lumps of soil from the next trench on the top without inverting. The soil and manure are mixed at harvest, thus giving an extra fertility boost to the following crop. (Though to call it 'soil' is rather a misnomer as it is solid clay. I once left a large pile of manure in one spot for about eight years and found that the worms had only managed to take it one inch into the soil.) Other interesting plants also volunteer themselves when you don't dig. I have had wheat, barley, corn, celery, raspberries, currants, roses and various trees. Clearly, manure alone would take years to build soil. Also, with the increasing price and unavailability of this wonderful substance, especially for those of us living in town, I became more and more interested in green manures. After reading Masanobu Fukuoka's One Straw Revolution I was totally inspired and decided to try his system out. I hope that by growing green manures there will eventually be no need to add cow manure.

The Trials Of Green Manuring

In the summer of 1992 after the spuds were lifted, I bought clover seed along with winter crops of broad beans, garlic and Japanese onions, confident that the clover would replace any nitrogen loss and act as a living mulch for the crops. During the winter, clover and crop did nothing, but come spring the clover took off. Having bought red clover instead of white clover by mistake (HDRA sell the white variety), it was over two feet tall before I gathered my wits about me. I then spent days hand cutting around each crop plant only to see it grow back - ridiculous! In the end I resorted to scything crop and clover every few weeks, adding other organic waste to the patch all summer and covering with black plastic over winter. In the spring an excellent tilth was revealed which grew good crops of sweet-corn and pumpkin.

In the next year the ex-spud patch received its white clover and alfalfa broadcast in May into standing crops of broad bean, Japanese onions and garlic. The ground was too dry and there was a poor take. Timing and conditions are critical and March/April are a better bet. Having suffered the slings and arrows of outrageous fortune, I still didn't give up. What follows below is a system based on gleaned information, past experience and intuition. My plot is a ten rod allotment (approximately 27m x 7m) and is divided into seven equal parts. It is almost exclusively a no-dig system (except for the rotating potato patch), taking an average of one to two hours per week to care for - most of this being taken up manuring and harvesting the spud patch.

The system is in its fourth year and works well. Fertility, soil condition and yield have all improved yearly, but I shall still continue to add farmyard manure, though in lessening amounts, because I cannot complete the circle of nutrients naturally. (Visions of me dashing up the road, toilet roll in hand notwithstanding.)

This virtually no-dig, green manure, low input system may not be the answer to Life, the Universe and Everything, but the allotment number is 42!