I have heard that a family of four can be kept fed 365 days a year using only 8 square metres of land. Is this really possible anywhere in the world? Could it really take only 2 hours a week as was suggested and what would be on the menu?
Opinions differ. There may be no definitive answer until somebody measures the output from 8 square metres of land 鈥� an experiment which is of necessity almost certainly going on in many poor countries 鈥� Ed
Energy flow is a key issue. The sun鈥檚 intensity at the Earth鈥檚 surface depends on latitude and season. The average value over a 24-hour period across the whole of the Earth鈥檚 surface is about 300 watts per square metre. Therefore each day, a 1-metre-square plot receives an average of about 26 megajoules of energy 鈥� more close to the equator. The recommended dietary intake is about 2000 kilocalories a day. So, in theory, an average 1-metre-square plot receives enough solar energy to support three people. However, photosynthesis has an efficiency of only 10 per cent so you would need more than 3 square metres per person. The figure of 2 square metres per person might just be achievable near the equator, although this seems optimistic.
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There are also difficulties in getting the required nutrients and minerals, and in seasonal reductions in output.
Simon Iveson, Pembangunan Negeri University, Yogyakarta, Indonesia
I don鈥檛 weigh my garden produce, but this year I did grow enough to fill a freezer, plus the produce my family ate fresh. All of this was grown on two small patches of land totalling about 7 square metres. I believe I could have grown the minimum daily requirements for two, or possibly even four, if that had been my intention.
The produce 鈥� interspersed and rotated 鈥� included runner beans, mangetout (sugar snap peas), onions, parsnips, raspberries, strawberries, spinach, broccoli, cauliflower and blackberries. I grew carrots, tomatoes, cucumbers, peppers, courgettes (zucchini) and herbs in pots on a square metre shelf in my greenhouse.
I grow more intensively than advised by seed packets, and I start most of the outside crops in a heated greenhouse in winter. Some crops, such as beans, take up very little ground space and crop rotation makes good use of space. In addition we eat wild fare, such as rabbits, and we could have supplemented our diet in various other ways had we not preferred to encourage the wildlife rather than eat it. Two hours a week on a plot this size is plenty of time.
But could it work anywhere? The soil in my garden has been cultivated for generations. I recently started a vegetable patch in an uncultivated part of the garden and the result was poor. And I鈥檓 not sure I could have grown enough to feed us out of season without a greenhouse or freezer.
Tony Holkham, Glanpwllafon, Cardigan, UK
My family has decided that it would be possible to feed a family of four from 8 square metres of ground for a year if we were only producing vegetables.
You can grow climbing beans up poles along the rear of the plot and freeze the surplus. You can also grow trailing plants, such as pumpkins or cucumbers, within the plot, but let them trail outside it. Silver beet can be cropped continuously and potatoes can be grown in a stack of old car tyres. Similarly tomatoes and Brussels sprouts grow upwards and you can bottle or freeze surplus tomatoes.
Herbs can be grown in pots with multiple openings, as can strawberries. Carrots, parsnips, swedes (rutabaga) and turnips can be grown between the tall plants. Stagger the plantings a little and freeze any surplus. Radishes are fast growing, so they need little space at any time, while celery is a 鈥渘arrow鈥� plant and the surplus can be frozen.
Keep seeds each year and store or barter the surplus seeds or grown vegetables for goods to preserve.
My garden is a little bigger than 8 square metres, but I haven鈥檛 bought green vegetables (or eggs) for a family of three for longer than I can remember. In our case we also have chickens, which fertilise the soil and enter the equation themselves because they provide food (but take up space).
鈥淭he vital part of this equation is growing vegetables that can be stored or preserved鈥�
The vital part of this equation, however, is growing vegetables that can be stored or preserved.
Sandra Craigie, Upper Hutt, New Zealand