What to do in your allotment in August

Lee Senior's Allotment overview

Written by Lee Senior

At this time of year the allotment is providing as much food as we can handle! The culmination of a year’s hard work, what a tremendous harvest it has been. Years like this certainly make up for the odd, less than perfect season.

For the last three weeks, I’ve spent all my spare time over at my plot – sunbathing, harvesting, hoeing and spot watering in that order. Thankfully, for now, the workload has eased, and I can enjoy some relaxing time there too. The biggest challenge has been getting enough moisture to the roots of thirsty crops such as runner beans, leeks and courgettes. My water butts have proved invaluable, though they’ve nearly run out at times.

Forward planning is key to a good plot that produces all-year-round food so my next focus is the Autumn-planting season. There’s still time to order your garlic bulbs and winter onion sets, if you haven’t already. My favourite over-wintering onion is ‘Radar’ as it’s particularly hardy and reliably ready to pick by early June. Of the red onions I prefer ‘Electric’ which I’ve also had success with as a spring sown onion set. Don’t forget to keep harvesting and happy gardening!

Allotment flowers in August

  • Pick sweet pea flowers regularly during August and remove any spent flowers and seed pods to discard.
  • Deadhead all of your flowering plants this month to keep everything tidy and prolong the flowering season.
  • Pick borage flowers to add to cooling summer drinks and salads. If you haven’t grown this versatile herb this year, make a note for next year. Its edible flowers are also insect magnets!

Allotment vegetables in August

  • Plant your winter vegetables out onto the plot if you haven’t already.
  • Sow spring cabbage seeds directly into an allotment bed to enjoy next year.
  • When your peas or beans have finished, clear the beds and follow with brassicas. Brassicas are hungry feeders and will benefit from the nitrogen boost that legumes leave in the soil.
  • Direct sow pak choi seeds in early August for quick crops of crunchy leaves.
  • Sow salad seeds like rocket and spinach now for quick-return leaf crops.
  • Sow rows of hardy spring onion ‘White Lisbon’, lettuce ‘Winter Density’ and radish ‘French Breakfast 3’ every few weeks from the middle of August to enjoy through the autumn and winter.
  • Direct sow lambs lettuce seeds outdoors. This compact salad leaf has a nutty flavour and crops all through the winter.
  • Plant late season potatoes this month to harvest in late autumn and winter.
  • Watch out for blight on your potato foliage this month, especially during prolonged wet weather. If blight is present you’ll find brown dead patches on infected foliage and stems. Remove affected plants immediately and burn. Try a blight resistant variety like ‘Sarpo Mira’ next year.
  • Pinch out the growing tips of your outdoor tomatoes mid-month to stop growth and divert energy to ripening the fruit.
  • Watch out for the symptoms of clubroot – wilted leaves and irregularly shaped roots. If your brassicas are affected, try resistant varieties like cabbage ‘F1 Kilazol’ next year. Clubroot persists in the soil for 20 years after infection so avoid spreading the disease around the allotment through shared soil.
  • Spray the floor of your greenhouse with water on warm days to raise humidity levels and deter red spider mites.

Allotment fruit in August

  • Cover your fruit bushes with netting as they ripen, or you may find the pigeons get there first! Raspberries are generally okay but strawberries, currants and blueberries will be guzzled if left unprotected.
  • When your summer-fruiting loganberries and raspberries finish, cut the fruited canes back to ground level.
  • If wasps are gathering around your fruit trees, use a waspinator to deter the flying pests.
  • Tidy your strawberry bed. Replace any plants that are more than three years old with fresh ones and remove dead leaves to improve airflow around them.
  • Give your trained apple and pear trees a summer prune. Cut this season’s new growth back by a third to expose the developing fruit to the light.

Crops to harvest in August

  • Some of the many crops in season include blueberry, cabbage, calabrese, cauliflower, carrot, French beans, lettuce, peas, second early potatoes, radish and spring onions.
  • Late summer is when tomatoes really come into their own. If you have a glut, make up batches of passata to freeze and enjoy over winter.
  • Your courgettes should be cropping furiously. If you have too many to eat fresh, try turning them into a chutney with other surplus produce, canning them or making and freezing soup.
  • Pick runner beans every day. If you find any tough pods missed in earlier summer harvests, add them to the compost heap.
  • For the best flavour and texture, harvest your beetroot when they’re a little bigger than a golf ball. Larger beets can become woody in the centre.
  • Sweetcorn should be ready this month. Peel back the leafy outer layer from one cob to check the kernels are nicely plump before picking.
Watering allotment

Image: Shutterstock

General August allotment jobs

  • Keep hoeing and weeding your allotment regularly as warm weather conditions continue through August.
  • Water your allotment often, avoiding the hottest part of the day to reduce evaporation and leaf scorch. Focus on newly planted crops to help them get established.
  • Keep an eye out for pests, as infestations can quickly get out of hand. Check your brassicas carefully for cabbage white caterpillars, removing any that you find. Look out for tell-tale clusters of green eggs that signal imminent hatching.
  • If you’re going on holiday, ask one of your neighbours to keep an eye on the plot and offer to return the favour. It pays to make friends with other plot holders.
  • Leave an area of your plot ‘messy’ to attract insects to pollinate and protect your crops against pests.
  • Watch out for slugs and snails in wet weather conditions. Copper tape can be an effective deterrent to keep them away from pots and containers. Sprinkle organic slug pellets around your ground crops to keep them safe.

Planning ahead

  • Order autumn-planting garlic, onions and shallot sets this month to plant at the end of summer. Split a multipack with an allotment neighbour to save money and avoid surplus.
  • Order broccoli ‘Stromboli’ seeds for sowing directly into a prepared seedbed next month. These broccoli plantlets provide an early crop of florets come spring.
Lead image: Lee Senior’s allotment
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About Lee Senior
Lee Senior is an experienced horticultural writer, RHS Yorkshire in Bloom judge and horticultural consultant. He has also had an allotment for over 25 years. After initially spurning horticulture as a career option, to pursue his boyhood dream of becoming a train driver, Lee soon realised he couldn’t resist getting his hands dirty to make a living. Horticultural College training led, to getting an allotment at the tender age of 18 (in the days when you could actually get a plot quickly). My gardening hero, is Geoff Hamilton” says Lee. “It was Geoff who convinced me that you didn’t have to spray everything that moved in the garden. Watching him on Gardeners’ World in the late 1980’s and early 1990’s was a revelation. I was lucky enough to meet Geoff and I’ve also more recently had the pleasure of meeting Joe Swift. Now over two decades of practical experience has taught me to work with mother nature, not to fight against her and don’t try to tame her, as so many gardeners seem to be on a mission to do. Small-scale food growing is my passion and I can’t wait for my two daughters, one who is 8 years old and the other who is 5 to hopefully pick up the baton in the future. Nothing beats the flavour and satisfaction of growing your own food. You simply cannot buy the same quality and freshness. Everyone can have a go at growing something says Lee, no matter where they live. Lee has also written his two books; ‘Pennine Way, The Highs and Lows’ which is a humorous, personal account of walking this momentous iconic walk. His second book ‘Walking in the Aire’, features 14 short walks in Yorkshire.