The glass struggle

Greenhouse and frame maintenance should be carried out a couple of times a year, ideally in early spring when you can clean the glass inside and out, wash down the staging and remove debris from guttering.

At this time of year, take advantage on dry days by making sure the glass fits snugly to the frame and replace any broken panes, wearing gloves and a pair of goggles. Use a hose and long-handled, soft-bristled brush to clean the roof glass, while you can take a washing-up cloth to the sides, going over all areas, because even if the glass looks clean, it will probably have a thin layer of algae on it. Where panes overlap, use a lolly stick or plastic plant label to ease out the dirt then give it a squirt with the hose.

Clean out debris from guttering and check that the brackets are sound and firmly attached and that there are no leaks. A leaking gutter is a common cause of rotting frames in wooden greenhouses. Small leaks can be repaired with a flexible, transparent, silicone polymer applied with a mastic gun, but for larger leaks, you may have to fit new gutters and downpipes.

Wooden frames need to be scrubbed clean with detergent and should be checked for rot. Cut back rotten wood to where it is sound and replace it with naturally durable wood such as pressure-treated timber. New bare wood should be treated with wood preservative. Aluminium frames should only require a quick brush over.

Once you have cleaned the outside, bring your plants outdoors if weather permits and remove weeds from the corners of the greenhouse and gaps between the paving stones of the path. Wash and clean the glass and frame inside, sweep away debris and wash down staging, which will help prevent problems from pests and diseases over the winter.

The resting stages of pests, especially the non-feeding adult females of red spider mites, can be hit hard by washing down. Allow the greenhouse to dry before bringing the plants back in.