Good hygiene in the greenhouse promotes healthy plant growth. Pests and diseases can overwinter in cracks and crevices, on greenhouse structures and equipment, so clean it at least once a year. Autumn is a good time to do this, before returning tender plants for the winter from outdoors. A spring clean is useful before starting spring sowings, but winter is difficult as plants cannot be moved outside. You can clean the greenhouse in sections moving plants to one end; alternatively cover all the plants with polythene sheeting.
Dirty
glass reduces winter light levels dramatically. An autumn clean will remove the last traces of shading. In cracks between the glass, moss and algae may build up. This can be removed with a non-scratch tool such as a plastic plant label or careful use of a jet wash attachment. Switch off electricity before washing down with a suitable detergent and rinsing with clean water. Choose a dry breezy day when the ventilators can opened to dry the greenhouse out.
Keep glass clean with occasional washes in the winter and before starting spring seed sowing. There is less need to keep the glass clean on the outside in summer as light levels are higher. A little dirt on the outside in summer may even be beneficial.
Clean down all surfaces and benches inside and wash gravel covering benches. Just Glasshouse Cleaner, marketed by Just Green, is based on seaweed extracts and suitable for cleaning all glasshouse surfaces. Wash and sterilise capillary matting, but preferably replace once a year. Wood frames can be treated with a wood preservative suitable for greenhouses available from DIY stores.
Throughout the year tidy up plant debris, weeds, fallen leaves and flowers, remove sick and dying plants, and sweep up regularly. This helps reduce fungal disease and removes debris and weeds that harbour pests.
Ensure good ventilation and allow capillary matting or soil surface to dry out periodically to avoid algae growth particularly in damp weather.
All pots and containers should be rinsed out and cleaned with a suitable detergent. This is a good job to do over the winter in preparation for propagating and potting up plants in the spring. Clean under the rim of pots which can harbour pests such as mealy bug. Sterilise pots with disinfectant. Clay pots will need soaking; leave to dry completely before use.