A regular exterior maintenance schedule will ensure that your greenhouse remains attractive and working efficiently all year round. The exterior will need to be cleaned, steel frames checked for rust, rotten wood replaced, broken glass or guttering repaired and hinges oiled.

Cleaning

Remove shading washes in autumn by rubbing them with a damp cloth or a brush. Dirt should be removed using a hosepipe and long handled brush, although you may find you achieve better results for ingrained dirt by brushing on a solution of kettle descaler. Make sure that you wear goggles and gloves when applying the solution, and then use a hose to rinse the glass thoroughly.

Dirt often becomes trapped between overlapping panes. Loosen this dirt and algae by pushing a long plastic plant label in between the gap and then wash away using the spray from a hose.

Checking the Framework

Check wooden structures for rotting wood and replace where necessary. Apply a coat of wood preservative to hardwood greenhouses every other year to prevent rot and restore colour. Softwood structures need a more regular schedule of painting; strip off loose and flaking paint every year, wash down, and apply a primer and a coat of good-quality exterior paint. Oil hinges and replace any that are rusting.

Check steel fittings and frameworks for rust; treat with rust remover wherever necessary. Repaint every 2-3 years.

Gutters

Clear gutters and make sure that downpipes have not become clogged. Use a hosepipe to give them both a good clean and to clear out any material that might be blocking them. Use mastic to repair small leaks, or replace sections that are leaking badly.

Repairing Panes

Glass or plastic panes that have small cracks may be repaired temporarily using transparent glazing tape. However, panes that are badly cracked or even broken should be replaced immediately to prevent draughts from damaging the plants.

Glass in aluminium frames may be replaced quickly and easily using the spring glazing clips. Glass in wooden greenhouses is slightly more difficult to replace, although well within the capabilities of most gardeners. Carefully remove the glazing tacks and the glass, and then chip away the linseed putty to create a smooth surface. Prime any unpainted or untreated wood on the glazing bars to prevent moisture entry, and then replace the panes onto a fresh bed of putty or glazing mastic. Secure them in place using glazing tacks.