Short answer - YES! You really do!
Crop rotation makes the best use of soil fertility and condition. If that was all there was to it, then in a small plot you could easily get round this by careful soil preparation. HOWEVER, the really critical role of crop rotation is in keeping pests and diseases at bay. As well as the obvious pests like slugs and snails, greenfly and flea beetle, there are others that lurk unseen. Potato virus. Pea and bean eelworm. White rot of onions. Clubroot. And so many, many more. These would really like you to grow the same plants in the same place year after year - it would allow them to build up to plague proportions and completely trash your crops. Many of the chemicals once available to control plant diseases have been withdrawn from use in recent years, so it is more important than ever to prevent problems before they arise.
Unfortunately, it's no good saying "I'll cross that bridge when I come to it."
If you rotate so the same crop doesn't occur in the same place for 3 or four years, diseases are unlikely to become a problem. However, if you wait until you have replant diseases, it will take a lot longer to get rid of them. Once in the soil, onion white rot (which will reduce your onion crop to zero) persists for seven years. That means you can't grow onions there again for at least seven years - much more inconvenient than a three- or four-year rotation. Plots in Ashford are getting smaller and smaller, and if you have disease in one part of a small plot, keeping vulnerable veg away from that area will be pretty tricky.
LAY OUT YOUR PLOT FOR CROP ROTATION RIGHT AT THE VERY START, BEFORE YOU EVEN START TO DIG OVER THE SOIL. That way, you can leave your paths firm and grassy, or set them out with boards rather than having to create them from soft, carefully dug soil.
If you rotate so the same crop doesn't occur in the same place for 3 or four years, diseases are unlikely to become a problem. However, if you wait until you have replant diseases, it will take a lot longer to get rid of them. Once in the soil, onion white rot (which will reduce your onion crop to zero) persists for seven years. That means you can't grow onions there again for at least seven years - much more inconvenient than a three- or four-year rotation. Plots in Ashford are getting smaller and smaller, and if you have disease in one part of a small plot, keeping vulnerable veg away from that area will be pretty tricky.
LAY OUT YOUR PLOT FOR CROP ROTATION RIGHT AT THE VERY START, BEFORE YOU EVEN START TO DIG OVER THE SOIL. That way, you can leave your paths firm and grassy, or set them out with boards rather than having to create them from soft, carefully dug soil.
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HOW CAN I ORGANISE MY PLOT FOR CROP ROTATION? IT'S REALLY SMALL!
The traditional three year rotation can be awkward to lay out on a small plot, resulting in rows which are either too long or too short. In fact, if you have a small plot, you probably won't be putting a third of it down to maincrop potatoes, the assumption made by the old schemes. A four year rotation will give you more variety and the chance to grow more of the delicate, expensive veg that you really want. |
Annie Austin's new plot, (photo from Allotment Life) laid out in four main beds with a fifth central bed, shows that even a tiny plot can be laid out beautifully for rotation. The central bed could contain herbs or a fruit bush. You could, if you wished, make the paths narrower, of course, omit the central bed, or adapt the shape for a more oblong plot.
Developing a rotation scheme
No-one can dictate your personal rotation scheme. How you organise your own crop rotation will depend on what you want to grow. These tips will help you group veg together and get them in the right order.
SUMMER VEG are usually grouped together - that means courgettes, potatoes, runner beans. outdoor tomatoes and sweetcorn. They enjoy similar conditions and are in the ground for about the same period (potatoes go in first as they only need protection from frost after they've come up). Not all of these veg need rotation as much as others, but they fit neatly together. They are in the soil from spring to autumn of the same year. This group likes a very fertile, humus-rich soil and many of them can be put in over compost trenches
PEAS AND BEANS have nitrogen-fixing bacteria in special nodules in their roots. This is one of the wonders of nature and an essential part of our ecosystems. It means that, once established, pea and bean plants put more nourishment back into the soil than they take out. For this reason, they are usually grown before the greedy brassica and onion families. The first peas and broad beans are usually sown in late autumn and are being taken out of the ground progressively as each row finishes, from spring onwards. Tender summer beans, like runner beans and french beans, can be grown in this section or with the summer vegetables.
BRASSICAS (the cabbage family) and ONIONS (including garlic and leeks) enjoy the same conditions and can be grouped together. [If you're the utterly organised type, you can really help protect your onions if you can remember to put them in the other end of the patch, with the brassicas going where the onions were four years ago, when they come round again to the same patch.] Both brassicas and the onion family like a humus-rich soil with lots of lime. It's usual to lime your brassica patch each year, so each section gets limed every three or four years. Remember, turnips and swede are also brassicas. The classic leafy brassicas like sprouts or cabbage are in the ground for a long time, being planted out in late spring to crop through the following winter and early spring.
ROOT CROPS like carrots, parsnips and salsify are usually grouped together as they need soil which hasn't been recently manured (see section on manure). You may not want to grow a full section of these crops, however. You can team them with salads or odds and ends, and prepare the soil specially for each type. Just remember carrots and parsnips want a soil which was manured the year before, not recently. If you are growing your carrots in raised containers to baffle carrot-root-fly, they may not feature in your rotation at all. Carrots can be grown as a fast catch crop with small varieties like Early Nantes and Chantenay, or as a winter vegetable with varieties like Autumn King or James Scarlet. You will definitely need to think about carrot root fly, either by growing resistant varieties like Flyaway, or by getting your carrots physically protected.
SUMMER VEG are usually grouped together - that means courgettes, potatoes, runner beans. outdoor tomatoes and sweetcorn. They enjoy similar conditions and are in the ground for about the same period (potatoes go in first as they only need protection from frost after they've come up). Not all of these veg need rotation as much as others, but they fit neatly together. They are in the soil from spring to autumn of the same year. This group likes a very fertile, humus-rich soil and many of them can be put in over compost trenches
PEAS AND BEANS have nitrogen-fixing bacteria in special nodules in their roots. This is one of the wonders of nature and an essential part of our ecosystems. It means that, once established, pea and bean plants put more nourishment back into the soil than they take out. For this reason, they are usually grown before the greedy brassica and onion families. The first peas and broad beans are usually sown in late autumn and are being taken out of the ground progressively as each row finishes, from spring onwards. Tender summer beans, like runner beans and french beans, can be grown in this section or with the summer vegetables.
BRASSICAS (the cabbage family) and ONIONS (including garlic and leeks) enjoy the same conditions and can be grouped together. [If you're the utterly organised type, you can really help protect your onions if you can remember to put them in the other end of the patch, with the brassicas going where the onions were four years ago, when they come round again to the same patch.] Both brassicas and the onion family like a humus-rich soil with lots of lime. It's usual to lime your brassica patch each year, so each section gets limed every three or four years. Remember, turnips and swede are also brassicas. The classic leafy brassicas like sprouts or cabbage are in the ground for a long time, being planted out in late spring to crop through the following winter and early spring.
ROOT CROPS like carrots, parsnips and salsify are usually grouped together as they need soil which hasn't been recently manured (see section on manure). You may not want to grow a full section of these crops, however. You can team them with salads or odds and ends, and prepare the soil specially for each type. Just remember carrots and parsnips want a soil which was manured the year before, not recently. If you are growing your carrots in raised containers to baffle carrot-root-fly, they may not feature in your rotation at all. Carrots can be grown as a fast catch crop with small varieties like Early Nantes and Chantenay, or as a winter vegetable with varieties like Autumn King or James Scarlet. You will definitely need to think about carrot root fly, either by growing resistant varieties like Flyaway, or by getting your carrots physically protected.
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SALADS like lettuce and other leafy stuff, especially spinach, are subject to very few problems with replanting in the same place. This means you can grow them as "catch crops", using any bit of ground which is temporarily empty or under-used. Beetroot are usually grouped with roots for convenience, but can also be grown with salads. You can also grow annual flowers, or plants like chrysanths or dahlias for cutting, in such gaps.
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If you want to follow a traditional 3-year scheme, but your plot is the wrong shape to split into three, consider splitting it into four, and using the fourth bit for plants which don't need to be rotated. This would include fruit bushes, herbs, and some salads. You are allowed to grow flowers on 25% of your plot, if you wish, so you could also put some flwering bulbs in this fourth section, for cut flowers.
Click on this link to go to the RHS website's article on crop rotation. Their suggestions cover both three-year and four-year rotations. They suggest that rotation isn't for very small veg gardens - from bitter experience we would disagree, any veg garden needs to think about preventing diseases and the smaller it is the greater havoc disease will wreak. They also suggest putting onions with peas, beans and roots. From experience we have found that does not leave enough room for everything you want to grow. Onions fit well with brassicas and that grouping allows more room for delicious peas and beans.
Click here for a really well-done, very informative illustrated talk on rotation online.
Another argument with the RHS approach is that it says lay out the beds each year according to how much you want to grow of a particular crop. Well, you can't easily change the size of the beds. A piece of ground can't be part of patch 3, one year, then part of patch 2 the next year; that would blow the whole idea out of the water and you'd have crops in the same ground for two years running. Moreover, different crops go in the ground at different times; the sowing season for peas and broad beans starts in November, potatoes go in during March ior April, and winter carrots are sown in July. If you also try to rejig the beds each year you'll get in a total muddle. We've seen people try and it leads to a great deal of bad language!
Click here for a really well-done, very informative illustrated talk on rotation online.
Another argument with the RHS approach is that it says lay out the beds each year according to how much you want to grow of a particular crop. Well, you can't easily change the size of the beds. A piece of ground can't be part of patch 3, one year, then part of patch 2 the next year; that would blow the whole idea out of the water and you'd have crops in the same ground for two years running. Moreover, different crops go in the ground at different times; the sowing season for peas and broad beans starts in November, potatoes go in during March ior April, and winter carrots are sown in July. If you also try to rejig the beds each year you'll get in a total muddle. We've seen people try and it leads to a great deal of bad language!
