hyacinth bulb

With schools out for summer and the holidays in full swing, our gardens become outdoor rooms for entertaining and taking life easy. Regular watering, feeding and dead-heading will keep flowers blooming and crops swelling, but there are plenty of other jobs to do so that gardens don’t run out of steam before autumn.

Our August gardening tips

Set up wasp traps

Wasps can damage ripe fruit in late summer and are a nuisance when you’re dining alfresco. Setting up traps can divert wasps away from outdoor living areas, reducing the risk of a painful sting. While garden centres have off-the-shelf wasp traps, it’s easy to make your own. Take an empty jam jar, half fill it with water and mix in a couple of teaspoons of jam. Cover the top of the jar with paper, secured with an elastic band, and punch a pencil-sized hole in the paper to allow wasps to enter. Place where wasps are a nuisance and they’ll be drawn into the trap by the smell of the sweet, fermenting liquid.

Dead liliesHelp flowers conserve energy

When lilies have finished flowering, dead-head by trimming back to just above a pair of leaves. This prevents plants from producing seed, which can lead to a lacklustre display the following year. To ensure an abundance of buds next season, ericaceous plants such as rhododendrons and azaleas need lots of water – do not let them dry out. Wisteria benefits from pruning after flowering; use secateurs to cut back side-shoots from the main branch network, reducing whippy growth to 20cm from its base, or five leaves from the main stem.

Lift onions

When bulbs have reached a mature size and foliage starts to turn yellow and keel over, it’s time to lift onions. Use a garden fork to carefully ease bulbs from the soil and leave them outdoors in full sun, ideally on a rack, to allow the crop to ripen. Before storing, check the bulbs and discard any showing damage, then place the crop in a cool, dry outbuilding such as a garage. While you’re on the veg patch, keep picking beans when they’re young and tender, and harvest second-early potatoes, courgettes, tomatoes and lettuce. Stake tall brassicas such as Brussels sprouts, to prevent heavy plants from toppling in the wind.

Trim lavender

Once lavender has finished flowering it will benefit from a light summer prune to clip away spent flower heads. This seasonal trim helps to keep plants compact and prevent unsightly, leggy growth. When cutting back straggly plants using hand shears, make sure there’s still new growth below the point at which you chop. If you prune too hard, cutting down to old wood, Mediterranean plants such as lavender can be reluctant to regrow and can die.

aphid on the green plantControl aphids

Aphids are a menace in August, infesting stems and leaves of garden favourites such as nasturtiums, dahlias and beans. Left unchecked, these sap-sucking insects can drain the life from plants and even spread plant viruses, while their sticky honeydew creates an unsightly mess. Organic solutions include blasting bugs from leaves and stems using a hosepipe (mildly effective) or using organic sprays, which are often based on sticky, fatty substances that block aphids’ ability to breathe and feed. Chemical bug killers offer effective control, with systemic sprays, which are absorbed by plants, providing long-lasting protection.

Harvest sweetcorn

Towards the end of the month, sweetcorn cobs will have swollen rapidly on plants, but how do you tell when they’re ready to harvest? Once the tassles have turned brown, there’s an easy test to see if cobs are ripe: peel back the husk and use your fingernail to pierce a kernel of corn. If the liquid that bursts out is clear, the cob isn’t ready and needs to remain on the plant for longer. However, if a milky solution emerges, the cob is at its peak. To harvest, twist the cob and pull it from the stem.

Install stepping stones

If frequently used areas of lawn are sparse and patchy – routes that lead to sheds and greenhouses are typical examples – installing stepping stones can reduce wear and tear and prevent muddy patches come autumn. Arrange stepping stones on the lawn where you want them to sit, then use a spade to cut around the slabs. Now move the slab aside and cut out the shape, so that the stepping stone will sit just below the level of the lawn to prevent your mower’s blades from striking the slab. Spread a level layer of sharp sand over the base of the hole before placing the stepping stone in position.

hyacinth in ceramic potPlant indoor hyacinths

It sounds bizarre to talk about Christmas in August, but if you want the intense fragrance of indoor hyacinths to fill your home on the big day, it’s best to buy bulbs now and plant them before the end of the month. Buy specially prepared bulbs and plant in pots or bowls filled with bulb fibre or multipurpose compost, so the tip of the bulb sits just above the surface. Water lightly then stand the pot in a cool, dark place – a garage is ideal. You can still plant hyacinths in September and October, but they may not flower until after New Year.

Prepare lawn seedbeds

If you’re planning to sow a new lawn in September or October, then August is the best time to prepare the seedbed. Choose a cooler day and dig the area, removing stones, debris and traces of weeds (including weed roots). If perennial weeds are a problem, spray with weedkiller in advance of digging, letting foliage die down before removal. Taking action now allows time for further weed treatment if regrowth is a problem. Digging, weeding and incorporating well-rotted organic matter into seedbeds, ahead of sowing grass seed in autumn, allows time for the soil to settle – perfect if you want to achieve a level lawn.

Keep compost moist

All summer we’re busy adding garden rubbish to compost bins, but the process where green waste breaks down into crumbly, nutrient-rich matter can grind to a halt if heaps become bone dry during hot weather. To keep the composting process running efficiently, use a garden fork to turn the contents, and add water to make sure that everything continues to rot. Keeping lids on compost bins will help to reduce moisture loss during hot spells.

How is your garden looking this summer? What other August gardening jobs are on your to-do list? Let us know in the comments.

Marc Rosenberg bio
Marc Rosenburg at Powderham Plant CentreMarc Rosenberg is a freelance garden writer and editor. A former journalist with Amateur Gardening and Horticulture Week magazines, he holds seven Garden Media Guild Awards. Marc has written for publications including The Garden magazine, BBC Gardeners’ World and RHS online.