Author Topic: Crop Rotation – Growing Methods for Gardeners  (Read 43 times)

Marie Shallcross

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Crop Rotation – Growing Methods for Gardeners
« on: February 03, 2019, 06:12:27 pm »
Crop Rotation – Growing Methods for Gardeners


Crop Rotation: – what is it? Do you need to use it for the crops in your kitchen garden or vegetable patch? Or is it only relevant for farms and large estates?

In order to ascertain whether crop rotation is right for your productive plot, we first need to look at what it is. A whistle-stop tour to its historical background will help with the pros and ocns.

Britain and Europe in the Middle Ages

Crop Rotation is a phrase which you may have first heard during a history lesson at school.
It is a method of cultivation used to improve soil fertility and plant health and therefore crop yields. Crops are grouped and grown according to their family.

The Medieval field system worked on a 3-course system of rotation. By Medieval, I’m referring to the approximate period 900 – 1400. Open fields were farmed as strips rather than whole fields. In other words, each tenant (freeholder or villein) had a certain acreage of land, but it was split up among different parts of the larger fields.


3-course Crop Rotation

           Field 1                   Field 2                   Field 3
Year 1   wheat or oats           field beans or peas     fallow
Year 2   field beans or peas   fallow                   wheat or oats
Year 3   fallow                   wheat or oats           field beans or peas

When left fallow in the third year for cattle and livestock were grazed on the field. The resultant manure helped improve the soil, as did the inclusion of peas and beans – a leguminous crop which helped fix nitrogen in the soil. Nitrogen is one of the three major plant nutrients.



Britain in the 18th Century

The farming and crop rotation breakthrough came in the early eighteenth century with the development of a 4-course rotation farming system. Viscount Townshend is credited with introducing this new method of crop rotation on his farms.

4-course Crop Rotation

           Field 1   Field 2   Field 3   Field 4
Year 1   Wheat   Clover   Oats or barley   Turnips
Year 2   Clover   Oats or barley   Turnips   Wheat
Year 3   Oats or barley   Turnips   Wheat   Clover
Year 4   Turnips    Wheat   Clover   Oats or barley

The benefits were mainly that animals could be grazed two years out of four, thereby increasing the fertility of the land.

Although a 4-course rotation farming system had been pioneered in sixteenth century Belgium, it was the take up of the system by the British combined with other agricultural related inventions and processes that led to the Agrarian Revolution. It is generally accepted that the Agrarian, or Agricultural, Revolution in Britain began a fundamental change which formed the driving force that became the Industrial Revolution of the nineteenth century.




Agriculture, Walled Kitchen Gardens and the Cottage Garden

One of the aspects of crop rotation which can be overlooked is that it started out as an agricultural system based on a monoculture; ie, one crop was grown per field. With the rise of the large, separate walled kitchen garden, which in Britain was from the sixteenth century, crop rotation became domesticated.

These kitchen gardens could be anything from 1 acre to 9 acres in size. This includes the external gardens that surrounded the walls but were still part of the overall kitchen garden. Dividing the garden into sections made planning, growing and harvesting much easier tasks. The quantities of food produced were large. They had to be sufficient to feed a large household, possibly 25 – 80 people, year-round.

The crops grown began to change as grazing cattle in a walled kitchen garden was most definitely not on the head gardener’s list!

Down a few social notches, the cottage garden food crops changed far more slowly. For example, potatoes weren’t a staple in English cottage gardens until some 200 years after their introduction into the country.

However, whilst the crops growing differed, the method of growing tended to be the same for the majority of hardy crops. By the nineteenth century, crop rotation had become the normal way in which vegetables were organised and grown in the field, walled kitchen garden, cottage garden, allotment and suburban gardens. As part of this system, vegetables and a great deal of fruit were grown in rows. These rows ran north to south across the plot.



How the System of Crop Rotation Works
 
Major concerns when growing the same family of vegetables year after year in the same patch of soil is that this monoculture system will cause: -

•   The build-up of disease specific to that family of vegetables. For example, club root in brassicas.
•   A less fertile soil, as even with manuring / fertilising annually, the same nutrients will be taken out, leaving the chemical constituency of the soil unbalanced. This in turn can lead to disease.

It may feel complicated to get the system of crop rotation right. But so long as the following are known, you have the basis to succeed: -
•   What type of soil you have
•   Your garden or allotment’s micro-climate
•   Which vegetables (and to a certain degree fruit) fit into which family groups

A 3 or 4-course rotation is the most usual to have as it is fairly simple. It is of course possible to sub-divide the plant family groups and make a 6 or 8 course rotation plan.

Including an extra, separate, bed for perennial vegetables is part of the vegetable garden plan, but not part of the rotation cycle. It is critical to make a plan of the four or more areas that are being used, and to keep up that record over the years.

It may help to imagine crop rotation providing a mixed diet for your garden or your clients’ garden, just as the fruit and vegetables grown provide a mixed diet for you.


Crop Rotation – Planning

There are two ways of approaching the grouping of your crops. They could be grouped according to their family or according to their cultivation needs. The two things aren’t always the same. Easiest to explain with an example for each.


3-course rotation grouped by family
 
           Bed 1   Bed 2   Bed 3
Year 1   Brassicas    Roots   Legumes
Year 2   Roots    Legumes   Brassicas
Year 3   Legumes    Brassicas    Roots


Example plants for each group: -

Brassicas
•   Cabbage
•   Brussels sprout
•   Broccoli


Roots
•   Beetroots
•   Carrots
•   Parsnips
•   Potatoes (which are a tuber)


Legumes
•   Peas
•   Runner beans
•   Broad beans
•   But also leeks, onions and tomatoes – which are not actually legumes

A 4-course rotation could have the onion family or potatoes in a separate bed
And we haven’t decided where to put the courgettes…



3-course rotation grouped by cultivation needs

Using the table as above, and using the same title for each of the groups, we get this as an example: -


Brassicas
•   Cabbage
•   Brussels sprout
•   Broccoli
•   Turnip
•   Chinese cabbage
•   Kale
•   Kohl rabi


Roots
•   Beetroots
•   Carrots
•   Parsnips
•   Potatoes
•   Swiss chard
•   Leeks
•   Onion


Legumes and ‘fruit’ vegetables
•   Peas
•   Beans – Runner, Broad, etc
•   Tomatoes
•   Aubergines
•   Summer Squash, eg Courgette
•   Cucumber
•   Winter Squash, eg Pumpkin


Using the “similar cultivation” method can be easier to manage in a smaller area. It works on the basis that, for example, whilst potatoes and tomatoes are the same family, tomatoes need less nitrogen and more potassium. Potatoes are also a good crop for breaking up new ground; tomatoes are not.


What else do you need to know?

Hopefully this brief outline has helped clarify crop rotation for you. Getting to grips with it does take planning, and keeping records is a sticking point for many gardeners. If you feel a couple of bespoke gardening lessons from Plews would help with getting your garden planning and vegetable garden organised, do please get in touch.

Crop rotation can be used with any of the following cultivation methods: -

•   Growing in rows
•   Raised beds
•   Square foot gardening
•   Deep beds
•   Lasagne gardening
•   No-dig gardening

Read “Growing Methods for Gardeners” (which you can also find on Allandscapers) for explanation of these. If the thought of crop rotation and planning and record keeping feels far too organised for you, there are other methods of cultivation, Three Sisters, for example.

I leave you with two important thoughts. Which are valid whether you’re growing for your own use or designing a kitchen garden for a client: -
•   grow what you would like to eat
•   if space or time is tight, then grow interesting fruit and vegetables that are best eaten fresh and/ or those that cost a lot



Marie Shallcross
Plews Garden Design