The system works on the basis that certain groups of vegetables may tend to attract similar pests and diseases. So before I do any rotating, I have to put my vegetables into these groups. Different rotation systems have different ways of grouping vegetables, but I stick to a simple three category system:

Roots

• Potatoes
• Carrots
• Parsnips
• Beetroot

Brassicas

• Cabbage
• Broccoli
• Swede
• Turnip
• Radish
• Kale
• Kohl rabi
• Brussel sprouts
• Cauliflower
• Pak choi

Others

• Peas
• Beans
• Onions, Leeks and Garlic
• Cucumber, Courgette, Squash
• Sweetcorn
• Salad crops (lettuce, mizuna, rocket etc.)
• Anything else that is not in Roots and Brassicas

With a three-group system I decide on three separate growing areas and then using these slightly different soil preparation methods:

Roots area – I add a general-purpose fertilizer about two weeks before planting or seed sowing. My favourite is chicken manure pellets but if you want to avoid animal materials you could use a compost containing comfrey or nettle leaves for added nutrients.

Others area – If I’m planning ahead, I’ll give the area a mulch of manure or compost over the winter or at least a couple of months before seed sowing. Then I add fertiliser two weeks before seed sowing.

Brassica area – I treat this the same as the Others area, but if I’m working in heavy clay soil, I’ll also add a sprinkling of granular garden lime a couple of months before seed sowing to break up the soil particles and allow the roots to access more nutrients. Brassicas also like firm ground to root into, so I tread over the soil to get a level, consolidated surface. You will also need to cover your crops in this bed with a fine mesh to stop butterflies laying their eggs on the leaves and prevent pigeons from eating them.

Once my soil is prepared, I allocate one group of crops to each bed. The following years I change the crop group in each bed in this order.

When I’m growing in pots or grow a diverse mix of crops in each bed, I find that rotating crops isn’t strictly necessary. In these circumstances I keep a close eye on my crops and if they have avoided infestations, I just aim to continue growing a broad range of crops in my space to avoid a build-up of particular pests. There are some exceptions to this -

• If my vegetables develop a problematic disease, such as potato or tomato blight I will make sure I don’t plant the same crop in that area for at least a couple of years.
• I often choose to grow my Brassica crops together, so they are easier to net against butterflies and pigeons.