Rotation

I use a basic four year rotation cycle and I pretty much follow this in the polytunnel too, although I don't grow potatoes in the polytunnel beds (I don't want potato volunteers constantly coming through). Potatoes are grown in containers early in the year, more about that in another post.

To remind myself of the rotation cycle I use the mnemonic Slugs Like Bad Apples, where the capital letter stands for the four vegetable groupings:
Solanum - potatoes and tomatoes etc.
Legumes - peas and beans,
Brassicas - cabbages, kale, turnips etc.
Alliums - onions and garlic, this group also contains the carrots and parsnips.

Crops such as lettuce, spinach, beetroot, chard don't really need rotation and can be slipped in where space is available.

Using the rotation cycle, on the same patch of ground, legumes follow solanum, and brassicas are the next crop with alliums being planted in the fourth year.

Different crops have requirements for particular nutrients, and rotation ensures that crops take these nutrients from the soil without depleting it. For example, brassicas require a fertile soil (with plenty of nitrogen) they enjoy freshly fertilised ground, but will leave enough for the follow on crop (alliums) to utilise without their companion crop carrots producing forked roots, which they would if grown on rich soil.

Rotation also minimises the risk of the crop suffering from pests and diseases, as a build up of the problem is less likely to occur if the crop is grown in different soil each year.

In a polytunnel the rotation tends to be on a rather quicker basis than yearly as you can grow a two to three crops on the same ground in one year. However I try to follow a rotation pattern as much as possible and keep notes or labels in the ground to remind me of what I have done. I also use the non-rotation crops to break the cycle. The spinach I sowed from freshly saved seed on the 19th August is now up and has followed an onion crop. It is a useful winter crop and will provide plenty of leaves in the early part of the year. I will make about 3 to 4 sowings, each sown after the last one has germinated.