What to do during August in your garden and greenhouse.

Your monthly gardening checklists

Flowers

  • Collect seeds as they ripen, from plants such as aquilegias, sweet peas and love-in-a-mist, choosing a dry day
  • Deadhead dahlias and other perennials to encourage a constant display of blooms
  • Keep camellias and rhododendrons well watered through late summer while their flower buds are forming
  • Prune lavender once flowering is over to maintain a compact, bushy shape, but avoid cutting into old wood
  • Prune rambling roses, removing up to a third of stems that have flowered, and tie the rest to supports
  • Keep pots and hanging baskets flowering by watering and deadheading regularly, and add tomato feed fortnightly
  • Take softwood cuttings of woody herbs, including lavender and hyssop, choosing non-flowering shoots
  • Sow hardy annuals in sunny spots to provide early summer colour next year
  • Set up an automatic watering system for pots and hanging baskets if you're going away on holiday - in the case of a hosepipe ban, drip or trickle irrigation systems are usually exempt, check your local water board for restrictions
  • Strim or mow areas of wildflower meadow, now that the plants have scattered their seeds
  • Take softwood cuttings from penstemons, choosing healthy, vigorous, non-flowering shoots
  • Remove any spent hardy annuals if you don't want them to self-seed
  • Plant autumn bulbs, such as colchicums, sternbergia and nerines, in pots and borders

Save seed from Aquilegias for more blooms next year

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Fruit and veg

  • Be vigilant for signs of tomato and potato blight, removing affected plants immediately to prevent spread
  • Summer prune both free-standing and trained apple trees, to encourage good fruiting in future years
  • Plant well-rooted strawberry runners into new beds
  • Pinch out the tops of outdoor tomatoes, as further flowers are unlikely to produce fruits that have time to ripen
  • Order saffron crocus bulbs (Crocus sativus) to plant in September, so you can harvest your own saffron this autumn
  • Use netting or fleece to protect blackberries and autumn raspberries from birds
  • Lift onions and shallots once their tops die down, then leave to dry in the sun
  • Cut back leaves on grapevines to let the sun ripen the fruits
  • Sow hardy crops such as land cress, rocket and lamb's lettuce for winter pickings
  • Harvest fresh herbs to freeze in ice cubes for winter use, or to hang up and dry, then store in jars
  • Plant a kiwi plant, to climb over a trellis, fence or arbour
  • Water crops regularly, especially during hot weather, use water from a water butt if possible. In periods of drought, there may be a hosepipe ban so water your crops with a watering can
  • Plant blueberry bushes into acid soil

Freeze herbs in an ice-cube tray for portion size storage

Greenhouse

  • Set up a capillary matting system to ensure plants have enough water if you're going away on holiday
  • Plant cold-stored potato tubers in large tubs in a greenhouse or cool porch, for harvesting at Christmas
  • Pouring water over the greenhouse floor every morning during hot weather can help to increase humidity - during periods of drought try to use grey water to help reduce mains water use
  • Plant up pots with 'Paper White' narcissus bulbs for fragrant indoor displays this Christmas
  • Remove the lower leaves of cordon tomatoes up to the lowest truss, to let more light and air reach the fruits
  • Start watering dormant cyclamen to bring them back into growth after their summer rest
  • Plant autumn flowering bulbs, such as nerines, lachenalia and veltheimia in pots indoors, for autumn and winter colour
  • Look out for pests and diseases on greenhouse plants, and treat any you find immediately
  • Harvest tomatoes, cucumbers and chillies regularly to encourage more fruits to form
  • Tackle vine weevil infestations by watering pots with a solution of biological control nematodes
  • Shade delicate plants in the greenhouse to avoid sun scorch on hot days

Fragrant Narcissus for Christmas

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House plants

For more house plant advice and inspiration visit our Growing and caring for house plants page

Garden maintenance

  • Cut laurel hedges with secateurs rather than a hedgetrimmer, to avoid half-cut leaves that turn brown
  • Clear weeds from cracks in paving and driveways before they get established
  • Remove problem lawn weeds, digging them out
  • Sow green manure to fill any bare ground
  • Summer prune wisteria by shortening all long sideshoots to about 20cm
  • Keep deadheading border plants, unless you want to collect their seeds
  • Remove suckers from roses or around the base of trees
  • Collect seeds and ripe seed pods from your favourite flowers and vegetables
  • Prop up any clumps of tall border plants that are starting to flop, using canes and string, or twiggy sticks
  • Prepare soil for sowing a lawn or laying turf during September and October
  • Go on regular snail hunts, especially on damp evenings, to reduce populations
  • Turn compost to speed up decomposition
  • During periods of drought or dry weather, be sure to water wisely, listen to this podcast episode with Arit Anderson for some top tips

Summer prune Wisteria

Offers

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