How to boost your veg patch through crop rotation
NATIONAL Allotments Week (August 10-16, nsalg.org.uk) is the ideal time for beginner gardeners to get to grips with plant families and crop rotation, for the best chance of success.
There are four major vegetable groups
■ BRASSICAS: Including cabbage, Brussels sprouts, broccoli, cauliflower, kale, kohlrabi, oriental greens, radish, swede and turnip.
■ LEGUMES: Peas, broad beans and clover, which is used as green manure. Legumes can fix nitrogen from the air in root nodules and if left to decompose in the soil, will be beneficial to later crops.
■ POTATO FAMILY: potatoes and tomatoes (peppers and aubergines can be grown anywhere in the rotation).
■ ROOTS: beetroot, carrot, celery, celeriac, parsley, parsnip, Florence fennel and all other root crops except swedes and turnips.
HOW CROP ROTATION WORKS...
CREATE one bed for each group of vegetables each year, moving them in the same order and direction, to avoid planting the same crop in the same place more than one year in four, to prevent root diseases.
This also helps make the most of their soil requirements, as brassicas and roots like a topdressing of lime, while potatoes and legumes prefer manured soil. Alternate treatments keep the soil balanced, while its structure benefits from having a deep-root crop one year and a shallow-root one the next.
Salads and other quick crops can be grown in the gaps between rows of slower-growing, bigger crops. Onions, pumpkins, salad leaves and stem and fruiting vegetables can slot in any space, although onions are often grown with legumes.
Don’t grow potatoes in the same spot two years running, as they will leave the soil depleted of nutrients. Add lime to the soil in autumn after growing potatoes, then grow peas or beans which are great nitrogenfixers, producing plenty of nutrients for any crop that follows them, including brassicas.
With root crops, don’t dig in manure before planting, apply it once you have harvested the root crops, so the soil will be replenished ready for potato planting. Perennial veg, including rhubarb, artichokes and perpetual spinach, should go into separate beds where they can be left undisturbed. Asparagus needs its own bed and will take a couple of years before you can harvest it.