In vegetable gardening, the system of rotation of crops materially assists production. Simply explained it means that the same crop is not grown year after year on the same plot, as this would exhaust from the soil the plant nutriments that particular crop needs and yet for crops of another kind the soil would be good. Again, one crop grown several years running on a particular piece of ground may be more liable to pest and disease attack, whereas a fresh vegetable is probably not susceptible to the same troubles. Root crops like carrots and parsnips will break up the lower layers of soil and can be followed by brassicas. Therefore an allotment or part can be divided into three sections and what is grown on No. 1 the first year is grown on the second section next year, and on the remaining section for the third year. On the first section for the second year another kind of crop is grown, moving to the second and third sections on succeeding years.
A third variety fills the first section for the third year, and passes to the other two in due course. Then the whole process is repeated, as the soil has renewed its fertility. As indicated in a later paragraph, some variation to suit needs and likings can be made in rotation crops, so long as their nutritional needs are approximately the same.
Beginners are often frightened- by the emphasis placed in textbooks etc. on rotation and it should be made clear that the recommendations are to some extent counsels of perfection, and need not be followed slavishly. Some crops can be grown on the same land year after year (provided the ground is regularly manured withetc.) Examples are onions, celery, leeks, runner beans and sometimes carrots.
Asparagus, globe artichoke, rhubarb and seakale (not covered in the table) are, of course, permanent crops. Cabbages and other brassicas should always be grown on fresh land each year to reduce the likelihood of club, especially on acid soils where this disease is more prevalent.
Last, but not least, the crops grown must obviously reflect the tastes of the household, so do notlong rows of vegetables which only make a limited appeal but more at intervals of crops which are especially to your liking.
The following table will act as a guide in carrying out a system of rotation, and also in applying inorganic fertilisers to particular plots in order to supplement animal manuring.
Group I — Crops requiring chiefly phosphates and potash: potatoes, peas and beans.
Group 2 — Crops requiring chiefly nitrogen and phosphates: cabbage, cauliflower, sprouts, broccoli etc.
Group 3 — Crops requiring nitrogen and potash: beet, carrot, parsnip, radish,
Certain crops requiring the three elements in more equal proportions — onions, leeks, turnips, celery and fruits — do not benefit by rotation.
They need ground that is manured every season.
If the plan is followed, as each crop matures the land will become free in time for the digging and planting or seeding of the following crop.
First Tear — Section A: beans, leeks, onions, peas, tomatoes, with beet, carrots and celery as succession crops. Section B: beet, carrots, parsnips, potatoes, with lettuce, onions and spinach in succession. Section G: broccoli, Brussels sprouts, cabbage, cauliflower, kale, spinach beet. Second Tear — Section C: beet, carrots, parsnips, potatoes, with lettuce, onions and spinach in succession. Section A: broccoli, Brussels sprouts, cabbage, cauliflower, kale, spinach beet. Section B: beans, leeks, onions, peas, tomatoes, with beet, carrots and celery in succession. Third Tear— Section B: broccoli, Brussels sprouts, cabbage, cauliflower, kale, spinach beet. Section C: Beans, leeks, onions, peas with succession crops of beet, carrots, celery. Section A: beet, carrots, parsnips, potatoes, swedes, with lettuce, onions and spinach in succession. See also ALLOTMENT, CROPPING PLAN, MANURES AND FERTILISERS.