What to do in the garden in August


  • Safeguard your tomato plants by removing lower level leaves to reduce its risk of disease and keep it thriving longer. Aim to leave 5-6 trusses of fruit per plant.
  • Water and feed sweetcorn with Ecoworm Soil Extract regularly. In hot summer, sweetcorn may be ready to harvest towards the end of the month. The silky tassels should have turned from yellow to brown, but don’t leave it until the tassels have withered up, or the sweetcorn will be past its best and tasteless.
  • Prune your perennial herbs, such as oregano and thyme. They will grow back each year without needing to be replanted. To keep them growing each year, trim them in August before the winter months. This will help them handle the frost.
  • Cut back herbs to encourage a new flush of tasty leaves that you can harvest before the frost. Dry or freeze excess herbs to use in the kitchen later.
  • Collect the ripe seeds of herbs such as fennel, dill and caraway for resowing.
  • Thin parsley to help it establish a good root system before winter. Leave 25cm space between each plant.
  • Feed tomatoes, cucumbers, peppers and aubergine plants with Ecoworm Soil Extract, which is high in potassium. Start feeding once the fruits start to form.
  • Pinch out growing tips of aubergines once they got 5-6 fruits. Pick fruits while they are still young.
  • Don’t allow more than 3 fruits on a squash plant. Make sure these fruits are established before pinching out the surplus.
  • Keep root vegetables well watered during dry spells or they will stop growing. If the rains come, there will be sudden surge of growth that will cause them to split.
  • Keep harvesting carrots, lettuce, beetroot, cucumber, radish, tomato, pepper, self blanching celery and endive.
  • Start blanching endive, to make them less bitter. The blanching process takes about two weeks. Cover each plant with a large, upturned flower pot. Cover the hole in the pot with a stone or cap of aluminium foil, to keep out all the light. Blanch the endive a few at a time, over several weeks, rather than all at once.
  • Continue harvesting second early potatoes. Also start harvesting your maincrop potatoes, once the leaves yellow and die back.
  • Spring-sown beetroot and carrots will be ready to harvest now. If you leave them in the ground, they will keep growing.
  • Pinch out the tips of your runner bean plants when they reached the top of their support. This will encourage side-shooting and more beans at a manageable height for picking. Check runner beans every day, and keep picking them before the beans begin to bulge or they will be tough and stringy. Pick them regularly to encourage the plants to continue flowering and producing more beans. Any left on the plant that go to seed will stop flowers from forming.
  • Harvest courgettes. Pick them before they get too big.
  • Lift and dry garlic, onions, shallots once the foliage has flopped over and yellowed.
  • Divide established clumps of chives.
  • Watch out for tomato and potato blight and get rid of any affected plants to prevent its spread.
  • Keep and eye on cabbage and white butterfly eggs under brassica leaves.
  • Keep the greenhouse ventilated.
  • Clear away any diseased foliage around your vegetable garden, to stop the disease from spreading.
  • Sow lettuce. It will give you crops in mid-to-late autumn. Think about protection when the night temperatures drop.
  • Sow winter or summer radishes. Give the summer radishes a partially shady spot, or they may bolt. Winter radishes will remain happily in the ground until you are ready to lift them for cold-weather salads.


  • Feed fruiting plants in containers with Ecoworm Soil Extract, which is high in potassium and will keep the plants alive and productive.
  • Plant out any rooted runners of strawberries for a good next year’s crop.
  • Harvest your fruit trees. Early varieties of apple trees will be ready towards the end of the month.
  • Continue training and summer pruning fruit trees grown against walls through August.
  • If you have too many raspberries, blackberries or loganberries, freeze them on trays for a couple of hours and then bag them to use later in year.
  • Protect your berries with netting or old net curtains, to keep the birds and squirrels away.
  • Finish summer pruning gooseberries and check for mildew and sawfly.
  • Prune fruited stems of blackcurrant bushes after harvesting.
  • Prune blackcurrants once they have finished fruiting. Prune few of the oldest fruiting canes to the ground level, and nip back the other branches to a healthy new bud.
  • Water melons regularly. If they have reached their full size and have stopped swelling, stop watering them and move aside, or cut off completely any leaves that are shading the fruit. Any flowers and young shoots should be nipped off.
  • Continue cutting out old fruited canes on raspberries. Tie in next year’s raspberry canes to support wires or fencing.
  • Remove any old straw from around the plants to improve ventilation and reduce risk of diseases. Detach young strawberry runners from their parent plants once rooted to make new strawberry beds. Check that new roots have formed by gently pulling on the runner.


  • Continue mowing and watering your lawn. If the summer has been hot and dry, there was not much new growth, therefore set mower blades high and leave the clippings to preserve the moisture. If the weather has been wet, lower the blades and collect the clippings.
  • Clear weeds from newly sown lawns.
  • Prepare areas for sowing or turfing next month, if you are planning on laying a new lawn this autumn.


  • Give hedges a final trim before they stop growing.
  • Take semi-ripe cuttings of shrubs (hydrangea, evergreen ceanothus, cornus, buddleia, philadelphus, deutzia and berberis). Pot them up individually to avoid root disturbance later. Keep the pots outdoors in a lightly shaded cold frame and remember to water the compost now and then. Late next spring you should be able to plant them out where they are to grow.
  • Start training standard fuchsias.
  • Continue deadheading roses, as this will prolong the flowering season. Spray them against black spot and mildew.
  • Deadhead lavender and collect the flower heads for making potpourri.
  • Take semi-ripe cuttings, and leaf bud cuttings of camellias.


  • Keep patio container plants well watered and feed with Ecoworm Soil Extract every two weeks.
  • Ensure that tall plants and especially large flowered dahlias, are well staked. Even without winds, the weight of the flowers can snap the stems, especially when raining.
  • Water camellias and rhododendrons thoroughly this month to make sure that next year’s buds develop well.
  • Trap earwigs, especially amongst dahlias, as they eat the young shoots and leaves at night. Other plants, such as, delphinium and asters are also at risk.
  • Sow butterfly flower (Schizanthus) and stocks now to give a green house display next spring.
  • Plant Madonna lilies, tender cyclamen and arum lily. Lilies begin growing new roots and leaves from late August. Choose a sunny spot and well drained soil. Plant them shallowly under 5cm of soil.
  • Dead-head bedding plants and perennials to encourage them to flower into the autumn and stop them self-seeding.
  • Cut back penstemon flowers as they fade to just above a leaf to encourage more flowers.
  • Start growing your tender cyclamen, if you haven’t yet.
  • Collect ripened seeds to store for the next year. Leaving some seed heads in place allows the plant to self-seed in the surrounding soil.
  • Pot up house-plant seedlings.
  • Mow wildflower meadows now to help scatter the seeds.
  • Take pelargonium cuttings.
  • Cut flowers for indoor display and for drying.

Read more:
What to do in the garden in July
What to do in the garden in September