Shading
Make sure your plants are well shaded on hot days to prevent scorch. The easiest way to do this is to apply netting or shade paint to the outside of the glass. Scorch is exacerbated if leaves are wet, so take care to water plants carefully.
Damping down
Damp down the greenhouse floor every morning on hot days to increase humidity. The plants will love this and it also helps to discourage red spider mite.
Tomatoes
Regularly pinch out any tomato sideshoots and tie the leading shoot to its support. Feed plants weekly with a high-potash tomato fertiliser, never letting them go short of water.
Cucumbers
Pinch out the tips of sideshoots to a couple of leaves beyond any developing fruits. Remember to pick any cucumbers regularly, as leaving old fruit on plants delays further flowering.

Supporting plants
Support the stems of tall perennials and lilies with bamboo canes and watch out for lily beetles and their larvae. Pick any off and destroy them immediately.
Deadheading
Deadhead roses as the blooms fade, cutting off the flowers just above the uppermost leaf on the stem. Trim back lavender bushes after flowering to remove the old blooms and shoot tips. Take care not to cut back too heavily into any old wood. Removing faded flowers from perennials and annual plants will also ensure a continued display of blooms.
Dried flowers
Cut everlasting flowers, such as helichrysum and achillea, and grasses, such as pennisetum, when they are at their peak. Hang them upside down in a warm, airy position to dry naturally, ready for decorative arrangements.
Prune wisteria
Summer prune wisteria this month, shortening their long wispy sideshoots back to about five or six leaves from the main framework. If the plant's flowering performance was poor last spring, drench the soil with a high-potash fertiliser for an improvement

Camellia
As long as they are planted in acid soil, camellias are not difficult to grow, and will even thrive in tricky semi-shaded areas, needing only minimal care once established. Most grow into large shrubs or small trees, but are extremely versatile and can be used as wall shrubs, hedges or superb container specimens.
For centuries, camellias have been popular in Japan and China, as can be seen on many of their works of art. Gardeners in Britain first grew these new plants in the early 18th century and by 1850, the camellia had become a prized ornamental shrub. Victorians loved the formality of the blooms and the elegant nature of the evergreen foliage. But, after the Victorian era, interest in camellias waned. Only in the 1950s did they become fashionable again, helped by the introduction of new varieties and species.
Camellia. japonica is the most popular garden species of camellia with the greatest number of varieties.

If I had to choose herbs 'must haves' to put in a window box on the sunny side of the house I would include chives, oregano, lemon thyme and a creeping rosemary to drape over the edge. However, on the shady side of the house I would have a salad herb window box which would include wild rocket, chervil, French parsley and red mustard.
When growing herbs in containers, I have two important tips. The first is to use a soil-based compost, either organic compost. This is because there are very few herbs that grow in peat, and a soil-based compost retains moisture which is a must to stop containers drying out. I also advise watering in the morning rather than the evening because this gives the plants a chance if the temperatures are hot during the day, especially for containers grown in full sun. The second tip is to feed container plants weekly from March until September. This keeps the plants healthy, helps them produce leaves, especially on cut and come again salads. I use a seaweed-based feed, however you can use any proprietary feeds that boost leaf production.