What is crop rotation?
Practising crop rotation is a great way to get the most from your vegetable patch or allotment, ensuring your vegetables will have the best possible chance of staying healthy and problem-free. At its simplest, crop rotation means avoiding growing vegetables from the same botanical family, in the same spot, for several years in a row. This prevents the build-up of pests and diseases and boosts soil fertility.
Growing crops in rotation used to be an accepted part of gardening and farming but fell out of favour as synthetic pesticides and fertilisers came to be used more widely. However, increased awareness of organic gardening, along with a greater knowledge of how the soil works, have seen a resurgence in the practise. There are no disadvantages to crop rotation apart from some advance planning and keeping notes to remember which crops have been grown where.
Most annual vegetables benefit from being fitted into a rotation but not all – there are quite a few ‘grow-anywhere’ crops that can be fitted in wherever and whenever is convenient. Perennial vegetables like asparagus and artichokes needn’t fit into a rotation as they stay in the same place.
What are the benefits of crop rotation?
- Crop rotation helps prevent a build up of soil-borne pests and diseases specific to a particular family of vegetables. Common problems such as clubroot (brassicas), white rot (onion family) and eelworm (potatoes) can’t take hold when the crop is moved around each year – the pest or disease life cycle is interrupted without a host plant
- Rotating crops annually balances out soil fertility. Different vegetables have varying requirements for nutrients and soil microbes, so moving crops around ensures that not too much is taken from the soil over a given time period
- Rotation groups are organised according to cultivation needs, making soil preparation and crop care easier and simpler
- Using weed-smothering crops like potatoes can help to prevent weeds for later sowings of crops like carrots
Vegetables that benefit from crop rotation
- Onion family (onions, leeks, garlic, shallots)
- Root vegetables (beetroot, carrot, parsnip)
- Brassicas (Brussels sprouts, cabbage, calabrese, cauliflower, kale, swede, turnip)
- Potato family (peppers, potato, tomato, aubergine)
Vegetables that don’t need crop rotation
Sweetcorn, peas, beans, salads, courgettes, squash, cucumber, radish. Fit these in anywhere that suits, though ideally not in the same spot for many years in succession.
How to do crop rotation
Make a list of the crops you want to grow and then divide them into separate growing groups. You don’t need to worry about crops growing in pots or growing bags as these can be completely emptied of old compost, cleaned out and refilled. Depending on how much space you have, you can rotate your crops in a three- or four-year rotation. If you have space, a four-year rotation is best.
How to do a three-year or 3-cycle crop rotation
In autumn or winter, prepare the soil according to the needs of each group. For example: brassicas are hungry plants that thrive on rich soil with plenty of added compost or well-rotted manure and do best in alkaline (limy) soil. Because root crops such as carrots and parsnips mustn’t be grown on freshly manured ground, these should always follow brassicas. Deeply dug and manured soil is also ideal for hungry crops like sweetcorn, courgettes, and squash.
To make the most of your growing space, under or inter-plant the main crop with fast-growing small veg like lettuce, mixed salad leaves, rocket, and radish.
First year
Bed 1 Potato family
Bed 2 Onion family and roots
Bed 3 Brassicas
Second year
Bed 1 Onion family and roots
Bed 2 Brassicas
Bed 3 Potato family
Third year
Bed 1 Brassicas
Bed 2 Potato family
Bed 3 Onion family and root
How to do a four-year crop rotation
A four-year or 4-cycle rotation adds legumes (peas and beans). Because their roots have little nodules that enrich the soil with nitrogen from the atmosphere, grow legumes a year in advance of brassicas, which have a high nitrogen requirement.
First year
Bed 1 Potato family
Bed 2 Onion family and roots
Bed 3 Legumes
Bed 4 Brassicas
Second year
Bed 1 Onion family and roots
Bed 2 Legumes
Bed 3 Brassicas
Bed 4 Potato family
Third year
Bed 1 Brassicas
Bed 2 Potato family
Bed 3 Onion family and roots
Bed 4 Legumes
Fourth year
Bed 1 Legumes
Bed 2 Brassicas
Bed 3 Potato family
Bed 4 Onion family and roots
No Fuss Guide to crop rotation
Watch our No Fuss video to rotating crops with David Hurrion, who demonstrates the best order for crop rotation on a four-year cycle.
from BBC Gardeners World Magazine https://ift.tt/kHCBYvr
