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 about harvesting and growing garlic read our 'how-to' guide.
Pick your courgettes while they are 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.
Resist the temptation to harvest more rhubarb stems. This allows the plant to build up reserves for next 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.
Water your fruit and vegetable
crops daily in warm weather. Try to ensure that they are 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
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 netting around your plants.
If you have plants fruiting in containers, make sure you give them a high potash liquid feed to keep plants 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 manufacurers 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 sideshoots after they have developed five leaves.
Prune your plum, apricot, peach and cherry trees now. Pruning these species in the summer reduces the risk of these trees getting 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 your blackcurrant bushes after harvesting.
Raspberries are shallow rooted so they will appreciate being watered generously in hot, dry weather.
In the greenhouse
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 have 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 over-heating in sunny weather.
Think about which bulbs you would like for next spring - now is the time to order ready for autumn planting.
Make a note of your gardens pros and cons at this time of year to remind you of any changes that you need to make for next year.
Other jobs about the garden
Try watering 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 is needed.
Water your containers 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 contents of your compost bins every month to keep it well aerated.
Keep bird baths topped up in hot weather.
Remove floating blanket weed from ponds 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 creatures caught up in it can crawl back into the water. Try using Pond Wizard to help clear weed from your pond.
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 is worth protecting them.
Look for aphidson the underside of leaves - rub them off by hand or spray with an insecticide to prevent them multiplying. Alternatively try using a 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 then 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 nemaslug. For container plants try using copper tape.