Brassicas are one of the most demanding crops you can grow on an allotment. Cabbages, kale, broccoli and their relatives take a lot from the soil, stay in the ground for a long time, and are prone to persistent pests and diseases if rotation is poor.
Once a brassica crop finishes, the bed is often left tired, compacted, and more vulnerable to problems if the next crop isn’t chosen carefully. This is where crop rotation really starts to matter.
This guide explains what to plant after brassicas on a UK allotment, which crops help the soil recover, which ones to avoid, and how brassicas fit into a sensible long-term rotation.
How brassicas affect the soil
Brassicas are heavy feeders with relatively shallow root systems. Over a long growing season, they place sustained pressure on the soil.
By the time they’re harvested, brassica beds are often:
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low in available nutrients
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compacted from repeated watering and hoeing
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carrying a higher risk of soil-borne disease
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relatively weed-free, but biologically tired
This combination means the next crop should restore balance, not continue the strain.
The best crops to plant after brassicas
The most effective follow-on crops after brassicas are those that either rebuild soil fertility or make good use of disturbed ground without demanding rich conditions.
Legumes are the ideal follow-on crop
Peas and beans are the best crops to plant after brassicas.
Legumes improve soil fertility by fixing nitrogen, helping to replace nutrients that brassicas have removed. They also cope well with soil that’s been worked and compacted.
Good options include:
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peas
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broad beans
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French beans
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runner beans
This pairing is a cornerstone of traditional allotment crop rotation and works consistently well in UK conditions.
Potatoes can also follow brassicas
Potatoes are another strong choice after brassicas, particularly where beds feel compacted.
They:
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break up soil structure
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suppress weeds effectively
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help reset beds for future crops
While potatoes are also heavy feeders, they serve a different role in rotation by improving soil structure rather than prolonging brassica-related problems.
Fast crops for the same season
If brassicas are cleared in late spring or early summer, there’s often time to grow a short-season crop before autumn.
Suitable quick crops include:
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lettuce
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spinach
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salads
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radishes
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turnips
These make use of cleared ground without placing additional long-term pressure on the soil.
Crops to avoid planting straight after brassicas
Some crops struggle if planted immediately after brassicas, particularly if soil hasn’t had time to recover.
Avoid repeating brassicas
Growing another brassica crop in the same bed significantly increases the risk of:
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clubroot
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pest build-up
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declining yields
Even if plants look healthy initially, problems often appear in later seasons.
Be cautious with roots
Root crops such as carrots and parsnips can struggle after brassicas if soil is compacted or nutrient-imbalanced. Forking and poor root development are common.
Roots usually perform better later in the rotation once soil structure has improved.
How brassicas fit into crop rotation
In most allotment systems, brassicas sit immediately after legumes and before lighter-feeding crops.
A simple and effective rotation sequence is:
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Potatoes
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Legumes (peas and beans)
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Brassicas
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Roots / alliums
In this setup:
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legumes rebuild fertility
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brassicas use that fertility
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lighter crops follow once pressure reduces
If you’re using a 3-year crop rotation, brassicas usually sit between legumes and roots.
What if space is limited?
On smaller allotments, perfect rotation isn’t always possible.
If space is tight:
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prioritise not repeating brassicas in the same bed
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rotate crop families rather than individual vegetables
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use legumes as often as possible after brassicas
Even partial rotation significantly reduces long-term problems.
Common mistakes after brassicas
Brassicas often cause issues because their impact isn’t obvious straight away.
Common mistakes include:
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planting another heavy feeder immediately
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assuming compost alone fixes rotation problems
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repeating brassicas in nearby beds year after year
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ignoring clubroot risk
These mistakes tend to show up gradually, making them easy to overlook until yields fall.
Planning what comes after brassicas
Because brassicas stay in the ground for so long, they can disrupt rotation planning if beds aren’t mapped in advance.
Being able to track:
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where brassicas were grown
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how long they occupied the bed
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what follows them next
makes rotation far easier to stick to and reduces accidental repetition.
Visual planning is especially useful when brassicas overlap seasons or share space with other crops.
Final thoughts
Brassicas are valuable crops, but they demand respect in rotation.
Follow them with legumes or potatoes, avoid repeating them too quickly, and let the soil recover before planting lighter crops. When brassicas are rotated properly, problems like clubroot and declining yields become far less common.