What to do in the garden in July

July is the perfect month for alfresco dining
Image: Blazebox 4 + 1 Gas Burner Barbecue from Thompson & Morgan

July brings long, warm days that continue late into the evening — perfect for pottering in the garden after work, hosting barbecues, and enjoying your beds and borders as they reach their peak.

For advice on what to get started this month, check out the ‘what to sow & grow in July’ page. In the meantime, here’s a list of jobs to keep on top of this July:

Timely tips

Keep terracotta pots damp to keep the roots cool
Image: Shutterstock

1. Summer can still throw out a few surprises — make sure tall plants and climbers are well supported in case of bad weather.
2. Water at dusk to reduce evaporation and use mulch to retain moisture around plants.
3. Terracotta pots are prone to evaporation so dampen the pot down to keep roots inside cool and damp.
4. Regularly deadhead bedding and perennial plants to encourage new blooms for as long as possible.

In the flower garden

Cut back geraniums to encourage new growth
Image: Geranium 'Best Red' F1 Hybrid from Thompson & Morgan

• Cut back faded perennial plants to keep borders tidy.
• As your penstemon flowers fade, cut them back to just above a bud to encourage more flowers.
• Cutting back growth in hanging baskets can encourage new flowers and foliage and will revive the display. Make sure you feed your baskets well after doing this.
• Cut back hardy geraniums and delphiniums after the first flush of flowers to encourage new growth and further blooms.
• Keep an eye on your newly-bloomed hydrangeas for hydrangea scale - a sap-sucking insect that can affect growth. Read our dedicated scale insects pest & diseases page to learn more.
• Continue to tie in and train new growth on climbing plants.
• Prune wisteria now. Just remove the whippy side-shoots from the main branch framework to about 20cm from their base (about five leaves from the main stem).
• Prune lupins to encourage more flowers.
• If you need to prune your deciduous magnolia, now’s the best time to do it.
• Divide clumps of bearded Iris so they have time to form roots and flower buds for next year before the cold weather arrives.
• Take cuttings from your favourite tender plants for overwintering indoors. Cuttings can also still be taken from shrubs and border perennials.
• Deadhead bedding plants and perennial plants to stop them self-seeding and to encourage further flowering.
• Deadhead your roses to keep them looking tidy. Leave the flowers in place if your rose produces attractive hips (seed pods).
• Deadhead sweet peas regularly to keep them blooming. Water daily in dry weather.
• Capture seed heads from dandelions and other weeds. Collect them before they get a chance to release their seeds and spread throughout your garden.
• Keep an eye out for pests on plants, early treatment is best.
• Stop rust damaging hollyhock foliage by pruning out affected leaves and/or spraying with a fungicide.
• Look out for clematis wilt. Symptoms include wilting leaves and black discolouration on the leaves and stems. Cut out all affected material and dispose of it in your household waste.

In the vegetable garden

It's time to pick your courgettes
Image: Courgette 'Defender' F1 Hybrid from Thompson & Morgan/Copyright: Alamy Stock Photo

• Pepper plants will benefit from being potted on into progressively larger pots.
• Train cucumber stems upwards to make the most of the space available. Simply tie in their long stems to vertical wires or use cane supports to create a wigwam of poles.
• If you're growing aubergines, pinch out the growing tip once they have 5 or 6 fruits. Pick fruits while they are young. You can expect to start harvesting mid to late summer.
• Nip off the growing tips of squash and courgette plants to encourage branching.
• Pinch out tomato side shoots each week. Cut off any leaves growing below the lowest ripening fruit trusses to improve air circulation and prevent diseases.
• Boost your tomato crop by regularly feeding plants with dilute tomato fertiliser once a week. If leaves look pale and yellow, feed more regularly.
• Feed crops with a general purpose fertiliser.
• Apply a high-potash fertiliser once fruits start to form on peppers, cucumber and tomatoes. You can use this on sunflowers too.
• Harvest garlic when the tops start to bend over and yellow. To find out more, read our 'how to grow garlic' guide.
• Pick your courgettes while they’re young. Regular picking encourages more fruit.
• Encourage more marrows by harvesting regularly. Marrows that form in July and August should reach a good size by autumn. Let their skins harden in the sun before cutting them later in September or October. They can be stored into winter.
• Pick, dry and freeze herbs for using later in the year.
• Pick runner beans regularly to prevent them becoming stringy and to make room for developing pods. Leaving mature pods on the plant can prevent further flowers forming and reduce your crop.
• Harvest beetroot, peas, carrots, chard, potatoes, salad leaves, lettuce, and tomatoes this month.
• Resist the temptation to harvest more rhubarb stems. Leave the stems in place; this will allow the plant to build up reserves for next year.
• Water your fruit and vegetable crops daily in warm weather. Try to ensure that they’re consistently moist.
• Use grass clippings as a mulch around potato plants to stop tubers near the surface from turning green. Alternatively earth up your potato plants as they grow. If you're growing potatoes in bags, gradually add more compost until the bag is full.
• Control slugs to prevent them damaging your crops. Try using a natural pest control to reduce numbers.
• Tackle blackfly on broad beans by pinching off any affected growing tips.
• Check for cabbage white butterfly eggs under brassica leaves and squash any that you find.
• Clear away any diseased and spent foliage on and around your vegetable plants to keep them healthy.
• Clear weeds regularly, as they compete with your crops for nutrients and water.

In the fruit garden

Enjoy harvesting your summer fruiting raspberries
Image: Raspberry 'Willamette' (Summer Fruiting) from Thompson & Morgan

• Thin out the fruits on your fruit trees to produce good sized crops. This also helps to prevent brown rot.
• Protect any developing fruits from birds and squirrels by placing mesh around your plants.
• If you have plants fruiting in containers, make sure you give them a high potash liquid feed to keep them healthy and productive.
• Feed lemons and other citrus fruit trees throughout summer with a special citrus fertiliser.
• Treat apple scab with a fungicide. Always read the manufacturer’s label to check the suitability for use on edible crops.
• Check the leaves of gooseberry bushes for sawfly larvae, which can completely strip the foliage in a matter of days. Jet them off with water or pick them off by hand.
• Peg down runners on your strawberry plants to create more plants for next year. If you don't need more plants simply remove the strawberry runners completely.
• Maximise your fig crop by pinching out the tips of side shoots after they’ve developed five leaves.
• Prune your stone fruit trees like plum, apricot, peach and cherry now. Pruning these species in the summer reduces the risk of silver leaf disease.
• If you've trained your apples and pears as cordons, fans or espaliers, give them their summer prune now to maintain a good shape.
• Prune the fruited stems of blackcurrant bushes after harvesting.
• Raspberries are shallow rooted so they’ll appreciate being watered generously in hot, dry weather.

In the greenhouse

Remove spent blooms from roses to keep them tidy
Image: Rose 'Special Anniversary' from Thompson & Morgan

• Check plants daily. Water first thing in the morning or in the evening to reduce water loss through evaporation.
• Harden off and plant out any plug plants that you’ve been growing on.
• Damp down your greenhouse on hot days to increase humidity and deter red spider mites.
• Open vents and doors daily to provide adequate ventilation.
• Use blinds or apply shade paint to prevent the greenhouse from overheating in sunny weather.
• Try hanging sticky traps to catch flying pests to determine which pest control is needed.
• Tidy up fallen leaves and flowers to discourage the spread of fungal disease.

Looking after your lawn

Make sure you adjust your mower blades in summer
Image: topseller

• This is your last chance to feed your lawn with a special lawn fertiliser to encourage healthy green growth.
• Water newly seeded or turfed lawns in hot weather. Don't allow new lawns to dry out.
• If you’re experiencing prolonged dry weather, set your mower blades higher to reduce stress on the grass.
• If your lawn is infested by ants, brush out the nests on a dry day. Always brush them away before mowing.
• Recut any lawn edges if needed and install lawn edging to make future maintenance easier.

Other jobs about the garden

Keep slugs away from young plants with copper tape
Image: Copper Slug Tape from Thompson & Morgan

• Water the soil around the base of plants rather than the foliage. Make ‘pools’ around individual plants so that the water is directed straight to the roots where it’s needed, use an auto-watering collar, or set up an automated drip irrigation system.
• Water patio plant perennials and baskets thoroughly in hot weather. Continue to feed them with a balanced liquid fertiliser every 2 to 4 weeks.
• Use water butts instead of tap water as often as you can when watering your plants.
• Turn the content of your compost bin every month to keep it well aerated.
• Keep bird baths topped up in hot weather.
• Plant floating pond plants, such as water lilies, in still water away from splashing fountains.
• Remove floating blanket weed from your pond plants by twirling it around a stick or garden cane. Before composting it, pile the weed close to the pond for a few hours so any displaced creatures can crawl back into the water.
• Keep an eye out for powdery mildew on plants. Remove any affected parts and spray with a fungicide to prevent further spread.
• Look after your aphid eaters — ladybirds, hoverflies and lacewings feast on greenfly and blackfly so it’s worth protecting them.
• Look for aphids on the underside of leaves — rub them off by hand or spray with an insecticide to prevent them multiplying. Alternatively use natural pest control such as Lacewing larvae.
• Keep an eye out for scarlet lily beetles on your lilies — remove and crush any you see. Also check for the sticky brown larvae on the underside of leaves.
• If your plants are wilting for no obvious reason, check for vine weevils by tipping your plants out of their pots and looking for 'C' shaped creamy maggots amongst the roots. Treat with nematodes if vine weevils are spotted.
• Prevent slugs attacking your young plants by using pest control. For container plants apply copper tape.

From your armchair

It's time to order spring bulbs
Image: Narcissus 'Citrus Sorbet' from Thompson & Morgan

• Order perennial plants online now ready for autumn delivery.
• Think about which bulbs you would like for next spring — now is the time to order for autumn planting.
• Make a note of your garden’s pros and cons at its peak to remind you of any changes that you need to make for next year.