If you're new to growing veg, it helps to understand what crop rotation is and why we do it
'Onion and root vegetables will survive with little water and are separate from legumes that require regular watering.'
Many people, when they first get an allotment, are so keen to start sowing that they ignore the principles of crop rotation. They clear some ground, sown and plant, and gradually work their way up the plot. This is fine for a year or two: you'll probably get good results, and it's a great way to learn what crops are easy and what crops need most attention. But, in the long term, you'll get better results for your efforts if you grow certain crops on a different area of ground each year. The aim is to reduce the build-up of diseases and thus reduce the need to use chemicals. In addition to this, certain vegetables add nutrients to the soil, thereby improving the ground for the next crop.
Four groups to rotate
There are four family groups of vegetables to rotate:
onions and roots, potatoes, brassicas and legumes.
Using this method of crop rotation, you need only apply manure to a quarter of the ground each year, to the site where the hungriest feeders – the brassicas – are planted. The grouping is also convenient; for example, onion and root vegetables will survive with little water, and are separate from legumes that require regular watering. And members of the brassica family grown together can be covered with a horticultural fleece to protect them from insects and pests.
Potato family
This includes tomatoes, aubergines and peppers. Potatoes benefit from the addition of organic matter, and this in turn benefits the pea family the following year.
Legumes
This includes peas, broad beans, French and runner beans, sugar snap and mange-tout.
Brassicas
This includes broccoli, cabbages, calabrese, Brussels sprouts, Chinese cabbage, radishes and other oriental greens.
Onions and roots
This includes all types of onions, chives, garlic, leeks and shallots, plus carrots, and parsnips. The onion family and root crops like soil that has been fertilised for a previous crop, so it makes sense that it follows on the site of last year's brassica family that will have been heavily fertilised with well-rotted manure. Root crops need no fresh manure and very little watering, and are grouped with onions in the rotation because they have similar requirements.
For the purposes of your notebook and when you are at the planning stages of what to grow, identify your divided plots as A, B, C and D.
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Non-rotation crops
These are crops not related to the four main groups, which can be fitted in anywhere to fill gaps. They are undemanding, nutritionally speaking. They include chard, beetroot and spinach, which benefit from manure that is high in nitrogen, but are not dependent on it. Other non-rotation crops, such as lettuces and salad leaves, do not need high levels of nitrogen, but will benefit from some organic matter to help lighten and enrich the soi. Crops such as rocket, parsley, chives, dill and coriander are not demanding of soil and can be sown in rows in any free space.
Marrows, courgettes and pumpkins thrive on moisture-retentive soil and the addition of well-rotted manure in the planting hole.
Sweetcorn is the least fussy about soil, so it too can be grown in any of the beds.
Catch crops
This is the term for a crop that grows fast and fills a gap in the ground for a relatively short time. Plants such as
beetroot, spinach, radish, coriander, rocket and
lettuce make good catch crops because they germinate fast and mature quickly. They can also be picked young: as soon as the ground begins to fill up with slower developing crops, such as kale or broccoli.
Sow a catch crop of radish with a slot-to-mature crop such as parsnip or parsley. The radish will emerge quickly to mark out the row, while the parship or parsley will come through later.
There is time to grow a crop of rocket between the supports of climbing beans which have been planted out in summer before the beans cast shade.
With sweetcorn, there is enough light to grow a row of dwarf French beans in the space between them.
Look further
This article is extracted from the book
Allotment Gardening – An Organic Guide for Beginners – by Susan Berger, published by
Green Books, priced £9.95. Susan Berger trained at the English Gardening School at the Chelsea Physic Garden. She runs a successful garden design company and her garden has been featured in gardening journals,
The Sunday Times and
Marie Claire Maison.
denotes Subscriber-only content | Wednesday 23 July 2008 | Help | Glossary 
