Shading, humidity and ventilation On warm, sunny days provide shade for plants, seedlings and cuttings. Increase the humidity by damping down the staging and floor. Provide adequate ventilation, but do not open side or top ventilators on the windward side of the greenhouse on windy days. Watering and feeding Give the plants plenty of water, and feed vigorous plants weekly with the liquid plant food. Controlling pests and diseases As weather conditions improve, introduce the predator Encarsia formosa to control whitefly. You may need to make two introductions to build up its numbers sufficiently to keep the whitefly population under control. Sowing cinerarias Towards the end of the month sow cineraria seeds. This will produce plants that will flower indoors from December onwards. Sow the seeds thinly in pans of John Innes seed compost, cover lightly with compost, and germinate at a temperature of 10-13°C (50-55°F). Prick out the seedlings into a seed tray as soon as they are large enough to handle and keep them watered and shaded. Planting out In mild areas plant out any vegetables raised in the greenhouse once they have been hardened off. Half-hardy bedding plants can also be planted out; many will be suitable for hanging baskets and containers. Move outside roses that have been forced in containers when they have finished flowering. Taking softwood cuttings Take softwood cuttings of suitable herbs, shrubs and perennials; take semi-ripe cuttings of clematis. Cucumbers Sow seeds soon as possible if this has not been done. Stop laterals growing from the main stems of cucumbers at two leaves beyond the first or second fruit, unless they are much preferred all-female flowered type which do not make laterals and which fruit on the main stem. Cucumbers with male and female flowers will also need subsequent sub-laterals pinched out as soon as they have made two leaves beyond their first fruit. Remove all male flowers and tendrils. Pinch out the male flowers on those cucumbers that produce male and female flowers. Females have an embryo fruit behind the bloom. Pollination adversely affects the flavour. Cucumbers with male and female flowers should also have the growing tips of sub-laterals pinched out two leaves beyond their first fruit. Melons Sow seed as soon as possible if this has not already been done. Plant out any melons raised from seed sown in April into cold frames, one plant to each frame light. Set out each plant on a mound of soil mixed with well rotted compost. Pinch out the growing point when the plant has developed four or five leaves. Avoid splashing or damaging the main stem at soil level, or damping off may occur. Peppers and aubergines Transplant young plants into their final positions when they are 10 cm (4 in) tall; a greenhouse border, growing bags or 20 cm (8 in) pots are all suitable sites. Pinch out the growing tips to encourage a bushy habit. Stake tall varieties. water in and damp down the greenhouse floor to keep the humidity high. Tomatoes Twist the stems of cordon tomato plants round the supporting strings, or tie them to canes, and remove sideshoots regularly. Feed the plants every week or ten days from the time the fruits on the first trusses begin to swell, using a high-potash fertiliser. In a cold greenhouse, plant tomatoes in the border, in growing bags, or in bottomless containers on a gravel base using the ring culture method. Vines Continue to guard against powdery mildew throughout the growing season. Thin and train in new shoots.