Monday, 24 October 2011

Crop Rotation 2: Deciding what to grow

Once I have decided that it is a good idea to practise crop rotation, the next stage is to think about how? I can see 3 different approaches:

a)     Minimal   One way is to keep things as simple as possible. Try to leave as long as possible between potato and brassica crops, at least 3 years.  Try not to follow one crop with another from the same family.  And, try to follow a below-ground crop with an above-ground crop.  And that's it.

This is an excellent method. For someone else. Unfortunately it wouldn't work for me. My memory and record-keeping are both as bad as each other. I would look at a bed in the spring and not have any idea. Did I have potatoes there last year? Or was that the year before. No, hang on, wasn't that where I slipped my sweetcorn? Or was that the bed next door?

No, I need something more systematic, so that I can look at a bed in my allotment this year, and automatically know which family of vegetables were there last year, and which will be next year.

(b)   Prescriptive   There are as many different ideas for crop rotation as there are gardening books in my local library. So why not simply adopt someone else's plan?  The problem with this is that it always involves compromise. And I don't want to compromise.

For example, some rotations consider roots a separate stage, and allocate the same amount of space to roots as to brassicas or legumes, say. Yet I need nowhere near as many beds full of roots as I do legumes, unless I group spuds in with them in which case  (notwithstanding the diametrically different soil requirements) I need a lot more.

Another example: many rotations suggest liming the soil after lifting potatoes and then growing brassicas. The problem with that, for me, is that my soil is very loose after the spuds, and brassicas need a firmish soil. Some gardeners will simply tread the soil to firm it, and then dig over afterwards, but as I have described elsewhere, I want to avoid treading on the soil if I can. I just don't want to dig!

c)  Personal     Rather than slavishly follow a rotation suggested by someone else, I suggest we recognize that we all want to grow different amounts and combinations of vegetables. Therefore every gardener’s plan should be individual, and tailored to his or her own requirements.

In order to design a system that suits me, I need firstly to list what vegetables I want to grow and how much space I need to devote to them.

I have 20 beds at my disposal, and want to have a 4-year rotation, neatly dividing the growing area up into 4 quarters.  This means that each stage of the rotation will consist of 5 beds.

Here is my vegetable wish-list:

Potatoes          1st Early – 1 bed
2nd Early/salad  – 1 bed
Maincrop – 3 beds           
Total 5 beds

Legumes         Peas – 1 bed
Broad Beans (overwintering) – 1 bed
Broad Beans (spring-sown) – 1 bed
Runner Beans – 1 bed
French Beans – 2 beds           
Beans for drying – 1 bed
            Total 7 beds

Alliums           Onions (overwintering) – 1 bed
Onions (spring-sown ) – 1 bed
Garlic – ½ bed
Shallots – ½ bed
Leek – 1 bed
            Total 4 beds

Brassicas        Calabrese – 1 bed
Brussel Sprouts – 1 bed
Sprouting Broccolli – 1 bed
Summer Cabbage – ¼  bed
Summer Cauliflower – ¼  bed
Autumn &Winter Cabbage – 1 bed
Spring Cabbage – ¼ bed
Overwintering Cauliflower – ½ bed
Kale – 1 bed
Turnips – ¼ bed
Swedes – ¼ bed
            Total 6¾  beds

Roots              Carrots –  ¾  bed
Parsnips – ½  bed
Beetroot – ½  bed
Chicory (forcing) – ¼ bed
Celeriac – ¼ bed
            Total 2¼  beds

Gourds:          Courgettes & summer squashes – ½  bed
                       Winter Squashes & pumpkins – 1 bed
                        Outdoor cucumbers, gherkins,–   ¼ bed
Total  1¾ beds

Other              Sweetcorn – 1 bed
                        Celery – ¼ bed
Miscelleneous  (lettuce, salad onions, hearting chicories, Spinach beet, ruby chard, mizuna, rocket, summer turnips, radish, autumn spinach) - ¾  bed
            Total 2 beds

(I have excluded tomatoes, aubergines and peppers from the list because I intend to grow them in the greenhouse.)

Now, as I have said, my allotment has 20 beds. However totting up the requirements above, it is clear that I need about 29 beds to grow everything I want.  So I need somehow to grow 9 extra beds-worth of vegetables in the same area

If I don’t want to compromise, I will need to organize my plot very efficiently, and grow more than 1 crop per season in a given space. This can be done it 2 ways:

(a)  Interplanting    This means growing 2 or more crops in the same space, one slow-growing, and one faster growing. By the time the slower-growing plant needs the room, the other crop has already been harvested.

(b) Successional Planting This means sowing or planting out a second crop tas soon as the first crop has been harvested.  Which involves starting one vegetable off somewhere else, either in a  seed bed, or in pots, modules or trays, and planting it out later in the season once the first crop has vacated the soil.

This method often requires a nursery or holding bed in which the young plants can develop to a viable size but at much closer spacings that they will eventually require.

Now that I have my wish-list of vegetables to grow, I need to work out what order to grow them in -   which vegetable best comes before or after another, and what treatment the soil needs in between.

And then I need to look the planting and harvesting dates of the veg in my wish-list, to find interplantings and successions that can work.

           

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