Summer Gardening Calendar

General tasks

Plant out summer bedding, prepare the soil in the planting area and enrich with compost before popping plants in to give you seasonal colour all through the summer. Remember to water the plants well after planting (even if it has been raining) and frequently after that to help the roots establish
Keep weeds down by hoeing between established planting and in between the vegetable rows.
Add tall canes and plant supports for taller growing subjects like lilies in the borders

Lightly spray tomato plants with water to aid fruit setting. Evening is a good time to do this to avoid scorching on the leaves
Pinch out side shoots on tomato plants and train tomatoes and cucumbers onto their supports
Harden off hanging baskets ready to go outside if not done already
Watch out for pests and use organic methods to eradicate severe infestations of whitefly and red spider mite
Water crops in growing bags and pots daily, adding a liquid feed once a week
Increase shading and ventilation to keep temperatures down on hot days

Slugs and snails make their presence felt at this time of year so take steps to eliminate or deter them before too much damage is done
Aphids are multiplying fast and can leave plants damaged. Wash them off either with a forceful jet of water or with a weak mixture of detergent and water.
Outdoor tomatoes and runner beans can be planted out now. Remember to stake with garden canes

Look out for woolly aphid on fruit trees, and spray any you find with soapy water
Cover strawberries with netting to keep birds off the fruit
The following vegetables can be sown outside now: radish, runner beans, calabrese, pak choi, mizuna, marrows, courgettes, chicory, kohl rabi, lettuce, marrows, swede, turnip, French beans and endive

Give wooden furniture an annual clean and brush up. Sand smooth and apply teak wood oil
Cut back growth hanging down from climbing plants on arches and pergolas

Trim Clematis montana if it is too large and overgrown
In hanging baskets and containers pinch out the tips of flowering plants to help them produce bushy growth and lots of flowers!
Continue to use a forceful jet of water on garden plants to wash off aphids
Remove faded flowers from early flowering perennials – e.g lupins and delphiniums. This will often encourage a second flush of flowers later on in the summer. Giving the plants a generous liquid feed will also encourage new growth
Remove seed heads from aquilegia to prevent spreading (unless you want it to!)

In the greenhouse

Check all plants daily and water as necessary
Ventilation is important at this time of the year. Open doors and ventilators every morning but close them on cooler evenings. Check that birds or cats are not getting in and use netting to deter them if necessary
Grow bags can dry out. Water as necessary or stand the bags on gravel trays
If you are unlucky enough to have an infestation of white fly or spider mite use a biological pest control at this time of the year. Ask at your local garden centre for advice on biological controls

Kitchen garden

In the herb patch woody-stemmed herbs such as thyme and sage produce lots of healthy new shoots at this time of the year. Take some of these shoots as cuttings. (see tips below)
Begin harvesting: beetroot and other crops are still young and tender and taste delicious. Early potatoes will soon be ready too (dig one root to check if the potatoes are too small)
Strawberries, raspberries, currants, cherries and gooseberries are all coming into season – lovely!
Sweet corn grown in pots can be planted out now in blocks (not rows)
Some vegetable crops can be sown outside: lettuce and salad leaves, radishes, spring cabbage and even dwarf French beans for a late crop
Onions will grow well and produce a good crop if well watered. They also respond to regular hoeing to reduce weed competition
Fruit trees have a natural June drop to thin out the crop but hand pick any small, damaged or diseased fruits

Keep an eye on variegated shrubs and prune out plain green shoots which will spoil the look of the plant
Continue to remove problem weeds – by hand, with organic treatments or (over a larger area perhaps) by smothering with old carpet
Mowing lawns is a regular job now – mow at least once a week, finish the edges neatly and add the mowings to the compost heap in small quantities (or in the green bin if you use one)
Mulch when soil between plants is weed free and moist. This will reduce annual weed growth, help reduce loss of moisture and look attractive too. Pay a visit to your local garden centre to see the variety of mulches on offer

Flower garden

Continue to water plants in containers. Pots are often in the ‘rain shadow’ of a house or their foliage acts as an umbrella so they can dry out easily even if it has been raining
Bright red lily beetles may make an appearance now so pick them off and destroy them immediately. Make sure tall perennials and lilies are supported with bamboo canes or flower supports
As flowers fade remove them on rose bushes, perennials and annual plants. After lavender bushes have flowered remove old blooms and shoot tips but avoid cutting into the old wood
Prune wisteria this month by shortening the long wispy growth to about five or six leaves from the main branches.

Greenhouse plants can be scorched on hot days and shading will prevent this. Use netting or shade paint and take care to avoid drenching plant leaves if possible
On hot days too plants benefit from an increase in humidity. Damp down (spray water on the floor of the greenhouse) and this will also discourage red spider mite
Greenhouse –grown tomatoes need a weekly feed of high-potash tomato fertiliser and regular watering. Pinch out side-shoots too and tie the leading shoot to its support
Pick cucumbers regularly and pinch out tips of side shoots above developing fruits

Pick courgettes regularly, when still small and tender, carefully cutting them from the plant with a sharp knife
Prune summer fruiting varieties of raspberries by cutting stems down to soil level after picking the last of the fruit
Main shoots and side shoots on gooseberry bushes need to be pruned back to five leaves to encourage to produce fruiting shoots for next season
Peg down strawberry runners from new plants. These will root and can be potted up to be added to the strawberry bed next season
The foliage on each strawberry plant can be sheared off and any debris cleared away.
When young winter vegetable crops have stalks about the thickness of a pencil transplant them into final growing positions
Sow outside now: Chinese cabbage, spring cabbage, radish and winter spinach

General

If you are away on holiday be sure your plants don’t dry out. Move any containers out of full sun so they are shaded at the hottest time of the day. Terracotta pots can be left on gravel trays topped up with water so they can gradually absorb the reservoir of liquid.
Generate more plants by taking summer cuttings from fuchsias, pelargoniums and tender perennials. These cuttings take root quickly at this time of the year and will over-winter well in a cold frame or greenhouse.
Hedge trimming continues.
Ants may nest in pots and containers. Stand pots in a large saucer of water to help deter them.
In dry weather leave lawn mower blades on the higher setting
Top up ponds as water evaporates and levels go down