Essential Gardening Jobs for Late Summer

As the heat of summer begins to fade, late August offers gardeners the perfect opportunity to prepare for the upcoming autumn season. With harvests underway and plants setting seed, now is the time to maintain, tidy, and plan ahead to ensure a healthy and productive garden well into the cooler months.

Ornamental Garden

• Take stock of the herbaceous border, noting poorly-performing plants for potential dividing, replanting, or replacing in the autumn.
• Take cuttings of many shrubs, especially those that have produced new growth after flowering.
• Check and support Michaelmas daisies before flowering; treat mildew with a suitable fungicide.
• Deadhead border plants regularly, weed consistently, and water if needed to prevent powdery mildew.
• Continue cutting dahlias, tie in new growth, and watch for greenfly infestations-spray in the early evening.
• Tie and disbud chrysanthemums based on variety, feed with chrysanthemum fertiliser, and mulch/water during dry weather.
• Start preparing sites for new lawns to be sown in autumn - allow weed germination cycles before sowing seed.
• Occasionally mow established lawns without collecting clippings to allow mulching - especially beneficial in drought.

Vegetable Garden

• Earth up and feed celery, fastening stems with string to keep hearts white and firm.
• Feed runner beans, marrows, and ridge cucumbers with liquid fertilisers.
• Prepare a dry, frost-free site for storing potatoes and other root crops through winter.
• Sow White Lisbon salad onion seeds for spring harvesting - choose dry borders to avoid winter losses.
• Make early sowings of spring cabbage.
• Continue harvesting crops like beans, onions, peas, lettuce, beet, radishes, and carrots as they ripen.

Fruit Garden

• Top up wasp traps to protect ripening fruit; cover special fruits like grapes with muslin bags.
• Pick early apples (e.g., Discovery) for immediate use - do not store.
• Plant out strawberry runners propagated earlier in cell trays into prepared beds.
• Prune raspberries by cutting finished fruiting canes to ground level; leave 6 strong new canes per plant.
• Continue harvesting plums and greengages.

Greenhouse / Polytunnel / Conservatory

• Apply spray-on shading to protect plants from sun scorch.
• In dry weather, use biological controls against thrips and red spider mites; damp down walls and surfaces as needed.
• Reduce watering of gloxinias and begonias as flowering finishes.
• Continue harvesting tomatoes from protected plants and feed with tomato fertiliser for developing trusses.
• Apply calcium liquid feed to prevent blossom-end rot in tomatoes.
• Pot up rooted cuttings taken earlier in the summer.
• Begin watering cyclamen corms to restart growth; replace surface compost and treat for vine weevil grubs.
• Harvest cucumbers and melons; top dress with well-rotted compost.