This guide forms part of our month-by-month allotment planting calendar.
August feels like late summer on the allotment, but it’s also the start of a quieter, more deliberate phase of growing. Days are still warm, but they’re shortening, and planting decisions now need to be made with the end of the season in mind.
This is no longer about filling every gap. August planting is about choosing crops that will reliably finish or set up harvests later in the year.
Understanding August Conditions on an Allotment
Soil temperatures are still high in August, which means seeds germinate quickly. However, the balance between warmth and daylight is shifting.
The key factors now are:
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shortening days
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moisture availability
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how long crops need to mature
Fast establishment is still possible, but long-season crops are no longer realistic.
What You Can Sow Direct Outdoors in August
August suits crops that grow quickly or tolerate cooler conditions later on.
Salad leaves are still worth sowing, especially cut-and-come-again varieties. Smaller, frequent sowings work best to avoid bolting in hot spells.
Spinach can be sown towards the latter part of August, when temperatures begin to ease. Early August can be too warm, but later sowings often perform well.
Radishes and turnips are excellent August crops. They grow quickly and cope well with late-summer sowing, making good use of space freed up by harvested crops.
Beetroot can still be sown early in August, particularly for smaller roots and autumn use rather than storage.
What You Can Plant Out in August
August planting-out is usually limited.
Seedlings raised earlier for autumn harvests, such as late salads or chard, can be planted into cleared beds. These crops benefit from established soil and consistent watering.
Anything planted out now should already be growing well — August is not the time to nurse weak plants into place.
What You Can Still Sow Under Cover
Most August sowing can be done outdoors, but under-cover sowing can help protect young plants from heat stress or pests.
Starting late salads or spinach under cover allows you to control moisture and reduce losses, particularly on dry or exposed plots.
Otherwise, trays and modules should be used sparingly.
Crops to Avoid Starting in August
August is not the time for:
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long-season crops
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slow-growing roots
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brassicas intended for large winter heads
These crops either won’t have time to mature or will struggle as daylight drops.
It’s also rarely worth starting tender summer crops at this stage.
How August Fits Into the Rest of the Season
August planting decisions determine whether your allotment transitions smoothly into autumn or winds down early.
Using space freed up by harvested crops keeps beds productive without overcommitting. Leaving some areas empty now is often the right choice, allowing soil to recover ahead of winter planting.
This is also a good point to start thinking ahead to overwintering crops and how beds will rotate next year.
Common August Planting Mistake
The most common mistake in August is planting with spring expectations.
Growth will slow as the season progresses. Crops sown now need to be chosen for reliability, not ambition.
Final Thoughts
August is about restraint and clarity.
Focus on crops that suit the time of year, make the most of cleared space, and accept that not every bed needs refilling. A well-judged August sets up a calmer, more successful autumn.