Raised Beds and Crop Rotation Q & A

I had this question about raised beds and crop rotation  from a new allotment grower and and thought it worth sharing my reply.

I have recently (3 weeks ago) taken on an allotment (5 poles) which was rather overgrown with weed/grass and have now strimmed this down and cleared all rubbish from the plot, which had been vacant for some time, so I can see the lie of the land.

There are a few (six of various sizes) very well made raised beds on the plot which I have now weeded and either covered for the time being but have already planted in 3 of the smaller ones and I intend to keep most if not all of the raised beds as these are mainly over to one side of the plot .

I have a large area now all down the long side of the plot which I will dig and clear of weeds to have my main beds and my question is what sort of size should I have these beds? Should they be 10x6ft or 8x4ft or larger? Should I have 5 beds to do 5 year rotation or would it be simpler to have 3 large beds for a 3 year rotation?

Any help would be much appreciated as this is the first time I have grown vegetables although I am a keen gardner.

By the way, your book Vegetable Growing Month by Month was delivered to me yesterday and I am already ploughing through it, wonderfully concise and easy to understand, I shall have to order the Allotment Guide soon

That’s a really interesting question, thank you. And thanks for buying my Vegetable Growing Month by Month! Hope you find it helpful.

Do You Need Raised Beds?

The first question to answer is do you need more raised beds at all? With a long established plot, it’s a fair bet that the soil has been cultivated deeply over the years. Constructing raised beds to gain a depth of soil is most likely unnecessary. Of course, with a very stony soil a few raised beds to grow carrots, parsnips and so forth may be a good idea.

Having said that, many people find defined beds easier to manage. If the weed situation gets out of hand they can tackle a bed a day rather than facing a large area or a whole plot with a sinking feeling that the weeds are winning.

Crop Rotation

I think you can worry too much about crop rotation. The simple three year system is generally adequate and a four year system perhaps better but once you get into five years or more, things get difficult to manage. I cover crop rotation here: Crop Rotation

Don’t try and be too rigid about a three course rotation. You might not want to grow a lot of one group but more of another. Some crops can be used to balance things out.  For example;  sweetcorn doesn’t fit the traditional groups so can go where you will.

Rather than split the plot into three or five permanent sections, I’d just lay temporary paths. Make these by laying cardboard with woodchip or even grass clippings on top. They can just be dug in as a soil improver at the end of the season. These would act as a marker for you. Keep things flexible until you know what and how you want to grow.

Raised Bed Size

I certainly wouldn’t build a raised bed 10 x 6 ft. You would find it very difficult to cultivate the centre without walking on the bed which defeats the whole idea. Where I have used raised beds, I’ve found 10 x 4 ft to be optimum. This gives easy access to the centre of the bed from the sides and it isn’t too long to walk around.

I also have a couple of raised beds that are a metre (3′ 3”) wide. These are not particularly easier to cultivate and they do reduce the proportion of growing area to path but it doesn’t make a huge difference in the greater scheme of things.

I’ve written about raised beds on the site here: Raised Beds – Vegetable Growing in Raised Beds

I also looked at the market gardener system of beds developed in North America here:
New Beds – Market Gardening Methods