‘Outdoor housework’ that keeps away pests and diseases
An essential job each spring and autumn is greenhouse cleaning to make sure plants get through the winter pest and disease-free. This goes for any structure that you’re going to be overwintering plants in – conservatories, porches, even sheds. Your number one priority is making sure it’s clean in early autumn and before you start sowing in spring too.
Not only must it be frost-free, but pest-free. Cleaning the greenhouse and conservatory is my least favourite job (apart from the pond), but a necessary evil. Here are more tips on keeping your greenhouse clean from Forest Garden. My plants have suffered in the past from aphids overwintering in cracks and crevices, as I couldn’t get to out-of-the-way places in my packed conservatory. Read more about cleaning tools and pots in my growing plants from seed post. Read more on why you need to windproof your greenhouse.
Plan for greenhouse cleaning
Here’s what you need to do in autumn to reduce the risk of pests overwintering:
1. On a mild day, take everything possible outside.
2. Scrub off any old shade paint from the summer.
3. Brush or vacuum surfaces to remove all debris.
4. Hose down the exterior and interior on a soaker setting to loosen any pests/eggs and lichen.
5. Wash down the glass with warm, soapy water and a sponge. A breezy day will mean it dries out more quickly.
6. Spray all surfaces with Citrox, a powerful organic citrus extract disinfectant for cleaning greenhouses, pots, staging, tools, seed trays, bird feeders and bird baths. It doesn’t harm plants, and it’s effective against bacterial and fungal diseases.
7. The glass is best done with an anti-bacterial washing-up liquid – it doesn’t streak.
8. Check that all ventilation panels/windows are working.
9. Finally, check over plants that you’re overwintering carefully BEFORE bringing them in. You don’t want them to be harbouring pests. Better to cut things like geraniums (Pelargoniums) back outside first. Check pot rims and bases for hidden slugs, snails, and vine weevils.
Endnote: After three incidents of serious wind damage after Storm Desmond (the big panels of tempered glass cost about £110 a time), I installed Vitavia’s glazing bars to replace the usual glazing clips. It’s worth doing this and splashing out the extra money as you’re building the greenhouse. It’s harder to retrofit – it took three of us five hours to do it.
