Crop Rotation

Definition

Crop rotation is the practice of growing a series of dissimilar types of crops in the same space in sequential seasons to avoid the build-up of pathogens and pests that often occurs when one species is continuously cropped. Crop rotation also seeks to balance the fertility demands of various crops to avoid excessive depletion of soil nutrients.

For the purpose of planning crop rotation, plants are grouped by family (because they make similar demands and have similar susceptibilities).

Here are some examples of frequently grown crops, by plant family (heavy nitrogen feeders are identified HF, light feeders LF, and nitrogen fixers NF):
 

Alliacae (LF);

Garlic, Japanese bunching onion, Leek, Onions - globe, pickling, Japanese, Shallots, Spring onion, Welsh onion

 

Cruciferae (HF);

Broccoli, Brussels Sprout, Cabbage, Calabrese,  Cauliflower, Kale, Kohlrabi, Mustard, Oriental Brassicas, Radish, Rocket, Seakale, Sprouting broccoli, Swede, Turnip

Leguminosae (NF);

Broad Bean, French Bean, Runner Bean, Clover, Fenugreek, Lupins, Pea, Tares, Trefoil

Compositae (HF);

Chicory, Endive, Lettuce, Salsify

 

Cucurbitaceae (HF);

Courgette, Cucumber, Gerkin, Marrow, Melon,  Pumpkin, Squash

 

Solanaceae (HF);

Aubergine, Chilli, Capsicum pepper, Potato, Tomato

 

Chenopodiaceae (HF);

Beetroot, Good King Henry, Red orach, Spinach, Swiss Chard, Spinach Beet

Gramineae (HF);

Sweet Corn

Umbelliferae (LF);

Carrot, Celeriac, Celery, Dill, Florence fennel, Hamburg parsley, Parsnip

Always plan your garden so that closely related vegetables are grown in a different place each year.

Where possible, group together crops which will be harvested approximately  at the same time, this makes it easier to vacate a reasonably sized area for the next sowing.

Vegetables may be divided into either four or six major groupings.

Crops grouped into 4. ( 4 year rotation ).

(1) Cabbage family

(2) Legumes which fix nitrogen such as Peas and Beans (3) Corn, Carrots, Beets, Onions (4) Cucumber, Pumpkin, Melon, Squash

Divide your garden into 4 areas and plant a different group in each area every year, beginning the rotation again at the end of four years.

Perennial vegetables such as Rhubarb & Asparagus should be grown outside of the main beds and not included in the rotation.

 

Crops grouped into 6. ( 6 year rotation ).

(1) Cabbage family

(2) Cucumber Pumpkin, Melon, Squash (3) Legumes (4) Corn (5) Onions, Garlic and Leeks (6) Potato family

Carrots, Celery, Parsnips, and Herbs may be added to any convenient group

Perennial vegetables such as Rhubarb & Asparagus should be grown outside of the main beds and not included in the rotation.

A typical example might be to grow potatoes (heavy feeders) on newly fertilized soil, follow these next season with peas and beans (which feed the soil), and then follow with onions (light feeders). In the fourth season, rather than planting potatoes again (which would give only a three year cycle), a different heavy feeder from a different family might be grown (e.g.. courgettes).

 

Example. Three Year Plan.

Year 1 Year 2 Year 3 Year 4
Bed 1 Brassicas, inc Swede & Turnip Beans & Peas, Tomatoes, New Potatoes Onions & Roots As Year 1
Bed 2 Beans & Peas, Tomatoes, New Potatoes Onions & Roots Brassicas, inc Swede & Turnip As Year 1
Bed 3 Onions & Roots Brassicas, inc Swede & Turnip Beans & Peas, Tomatoes, New Potatoes As Year 1
 

 

Example 1. Four Year Plan.

Year 1 Year 2 Year 3 Year 4
Bed 1 Brassicas, inc Swede & Turnip Beans & Peas, Tomatoes, New Potatoes Onions & Roots Leave Fallow or grow Green Manure
Bed 2 Beans & Peas, Tomatoes, New Potatoes Onions & Roots Leave Fallow or grow Green Manure Brassicas, inc Swede & Turnip
Bed 3 Onions & Roots Leave Fallow or grow Green Manure Brassicas, inc Swede & Turnip Beans & Peas, Tomatoes, New Potatoes
Bed 4 Leave Fallow or grow Green Manure Brassicas, inc Swede & Turnip Beans & Peas, Tomatoes, New Potatoes Onions & Roots

 

Example 2. Four Year Plan.

Year 1 Year 2 Year 3 Year 4
Bed 1 Potatoes Beans & Peas, Leeks, Lettuce Cabbage, Winter greens Carrots, Beet, Turnips, Parsnips
Bed 2 Beans & Peas, Leeks, Lettuce Cabbage, Winter greens Carrots, Beet, Turnips, Parsnips Potatoes
Bed 3 Cabbage, Winter greens Carrots, Beet, Turnips, Parsnips Potatoes Beans & Peas, Leeks, Lettuce
Bed 4 Carrots, Beet, Turnips, Parsnips Potatoes Beans & Peas, Leeks, Lettuce Cabbage, Winter greens