Repairing, cleaning and disinfecting Prepare the greenhouse for autumn and winter use by making any necessary repairs, such as replacing broken glass and renewing rotten wood. then set aside time to give the greenhouse a thorough clean and fumigation. This will help to prevent problems from pests and diseases over the winter. Before cleaning the inside, remove all the plants, turn off the electricity and protect any sockets with clear plastic. Clean out all the pots, boxes and trays, and scrub containers before storage or re-use. Remove plant debris and other rubbish. Thoroughly clean the inside of the glass with a hosepipe and brush. To remove dirt trapped between overlapping panes, first dislodge the particles with a plastic plant label or a similar flat, flexible implement, then thoroughly rinse it off with water. Use a greenhouse disinfectant to clean the glazing bars, staging and floor; wear protective clothing while doing this. If your greenhouse has removable staging it is usually easier to dismantle it and clean it outside the garden. When cleaning is completed, put the plants back in the greenhouse, close all the vents and fumigate everything with a smoke cone. Controlling pests All the usual greenhouse pests will remain active and breed rapidly in the warm weather. Biological controls are very effective in a greenhouse, but be careful not to destroy them with insecticides. Taking cuttings Take cuttings of perennial plants, herbs, carnations, pelargoniums, shrubs and rock plants that you want to propagate. Pinch out fuchsias to encourage shoots for cuttings. Sow herbs in large pots for winter. Sow seeds of lilies and propagate by planting bulbils. Garden maintenance Greenhouse and frame maintenance should be carried out at least a couple of times a year if possible, and August is a good time to tackle the job as it is still warm enough to move the plants outside if you require full access. Make sure the glass fits snugly to the frame and replace any broken panes. In an aluminum greenhouse the glass is held in by glazing strips which can be unhooked, but in a wooden greenhouse they may be fixed with beading, glazing bars or putty. Wet gloves when handling glass. Cure any stubborn leaks around the edge of panes, by covering glazing bars with mastic tape. Clean out debris from guttering and check that the brackets are sound and firmly attached. Check for leaks - a leaking gutter is a common cause of rotting frames in a wooden greenhouse. Small leaks can be repaired with mastic, but for larger leaks fit new gutters and downpipes. Check the wood on frames and staging. Cut back any rotten wood to where the wood is sound and replace with naturally durable wood, such as western red cedar or pressure-impregnated timber. Rub down new bare wood with steel wool. Seal knots of shellac knotting, then paint with an exterior wood stain or primer and gloss paint. Strip off the old paint if necessary (remove nearby glass if using a blow torch), then rub down. Clean glass thoroughly, but be prepared to reapply shading if the summer is hot and sunny. Replace broken or cracked panes - this will look better and reduce the risk of further damage in high winds. Cold draughts will also be reduced. Pay particular attention to gaps between the panes, where dirt and algae can accumulate. Clean these out by pushing a thin label between the panes, then use a jet of water from a hose or compression sprayer to remove the loosened dirt. Take the opportunity to disinfect staging and fumigate as appropriate. Potting up Pot up seedlings sown last month and move cuttings into individual pots when rooted. Peppers and aubergines Harvest the first fruits. Continue to water, but reduce the amount towards the end of the month. Tomatoes Remove the growing tips of tomato plants by the middle of the month to encourage rapid development of the fruits on the top trusses. At the end of the month discontinue feeding and reduce watering. This helps to prevent the fruit splitting. If the nights turn chilly, close he ventilators early in the evening. Vines Continue to water and feed regularly, reducing the watering as the fruit starts to ripen. Splitting fruit, a common problem, is usually caused by allowing the soil to become bone dry between drenchings. Remove any fruit and leaves affected by mildew to stop it from spreading.