Jobs Ahead in August and September

In The Garden

Keep container plants well watered and feed with a liquid fertiliser every fortnight, even after heavy rains, as leafy foliage may prevent rainwater from reaching the compost.

Hedges can be given a final trim now so they look good over winter. Start by cutting the top flat and then trim the sides, ensuring that the top is narrower than the base.

Late summer-flowering shrubs like choisya, phiadelphus, weigela, and wisteria can be pruned now after flowering. Prune wisteria by removing all the whippy side shoots to around five leaves from the main stem.

Prepare areas of your lawn for se-seeding in September. Early autumn is an ideal time to fix bald patches or establish a new lawn. Remove any perennial weeds and stones and level the surface to be resown.

Strim or mow areas of wildflowers now that plants have scattered their seeds.

In The Borders

To ensure floral displays continue to bloom for as long as possible, deadhead spent flowers on roses, dahlias, cosmos, petunias, and anything else in bloom regularly. Once a plant has flowered and set seed, it will stop flowering unless prevented by regular dead heading.

Stake tall or top-heavy plants like dahlias, Shasta daisies, and lilies to prevent wind damage.

Keep watering rhododendrons and camellias to make sure that next year’s buds develop well.

Lightly trim lavender plants after flowering to keep their shape compact and to promote new growth. Trim spent flowering spikes back and take about 2.5cm from the leafy growth at the tips of shoots.

Cuttings of tender perennials like pelargoniums and fuchsias can be taken and will quickly root at this time of year to be overwintered on a windowsill.

Choose a dry day to collect ripened seed from plants such as aquilegias, sweet peas, and love-in-a-mist to store for next year.

In The Veg Beds

Maincrop potatoes can be harvested once they have flowered and should be ready to harvest through August and September. Make sure they are completely dry before storing in a dark, dry place.

Onions should be ready to harvest by early September. As soon as the top growth goes brown, bend it over to aid ripening, then ease the bulbs out of the earth on a dry day. Rest on the soil or on a drying rack to dry completely before storing. Onions should be stored in a light spot.

Hardy vegetables such as broccoli, cabbage, and Brussels sprouts can be planted out now so they are ready to be harvested throughout the winter months. 

Fill gaps left from harvesting by sowing lettuce, rocket, Pak Choi, kale, and chard.

In The Fruit Cage

Cut down canes of summer fruiting raspberries once they have finished cropping and tie in new canes to supports.

Runners of new strawberry plants can be secured into pots of compost or pegged down in the soil to allow them to root. Remove foliage of established strawberry plants just above the crown of each plant. 

Main shoots and side shoots of gooseberries can be pruned back to five leaves to encourage fruiting shoots to be produced for next season.

If you have a glut of ripe gooseberries, blackberries, autumn fruiting raspberries or other berries, pick them and either freeze initially on trays individually for storing or make them into jams to enjoy.

In The Greenhouse

Side shoots on tomatoes should be pinched out regularly and leading shoots continued to be tied to supports. Remove the lower level leaves from your tomato plant to help reduce the risk of disease. Watering should continue regularly and a high potash tomato fertiliser feed applied weekly.

Tips of cucumber side shoots should be pinched out just two leaves beyond any fruit that may be developing. Pick fruit on a regular basis as old fruit left on the plants will affect further flowering.

Sow winter lettuce and radish.

In The Herb Bed

Cut back perennial herbs now like thyme and oregano to encourage a new flush of tasty leaves to harvest before winter.

Established clumps of chives can be lifted and divided now.

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