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In a report published on 4 November 2026, Amateur Gardening editor Kim Stoddart advises gardeners to remove plant debris from greenhouse and polytunnel covers, store containers and keep some airflow through winter. She says cleaning and promptly repairing cover damage can help preserve light transmission and extend the useful life of the plastic.
Amateur Gardening editor Kim Stoddart has published an autumn maintenance checklist for greenhouse and polytunnel growers, advising them to remove foliage from covers, check for damage and provide brief periods of ventilation as temperatures fall. The recommendations are aimed at preserving light and supporting plants through winter, when enclosed growing spaces may be kept closed more often to retain heat.
Stoddart says foliage from tall-growing plants, including grapevines and tomatoes, can stick to plastic covers and rot. If it remains in place, it can block light and, over time, erode the plastic. Fallen leaves can also cling to the outside. She recommends starting with the inside of the structure, using a hose spray and a sponge or soft brush to remove plant material and wipe surfaces.
She advises waiting until most autumn leaves have fallen before cleaning the outside of a polytunnel. For hard-to-reach areas, Stoddart describes tying bedsheets together and pulling them back and forth over the cover with another person’s help. The report also recommends repairing cover damage as soon as it occurs. Stoddart says keeping the plastic clean and in good condition can help maintain ultraviolet light levels inside and extend its useful life.
For pots and trays, her approach is to empty used compost onto beds or borders, shake planters and store them for the next growing season. She says she does not routinely wash her trays, but advises cleaning them if a grower is concerned about a particular pest, disease or eggs. Stoddart also describes doubling up split plastic trays so they can remain in use.
Protecting Light and Winter Growth
Autumn maintenance affects how much light reaches plants and how well a covered growing space can be used during colder months. Debris left on plastic can shade crops, while unrepaired tears may compromise the cover. Stoddart presents cleaning and timely repairs as practical steps that may help gardeners get more use from their structures rather than replacing covers prematurely.
Ventilation presents a seasonal trade-off. Keeping doors and windows closed for longer can help retain heat as temperatures drop, but Stoddart says growers should still open them briefly, if possible, a few times during the week. In her advice, some airflow helps reduce the conditions that can contribute to fungal disease. She also recommends removing yellowing lower leaves and continuing to pick suitable leaves so plants can maintain growth and production over winter.
The guidance is relevant to home growers deciding how to prepare enclosed growing areas without abandoning winter crops. It also offers a low-cost approach to reusing containers, while acknowledging that suspected pest or disease problems may call for more cleaning than Stoddart’s usual routine.
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The End of the Main Growing Season
The report appeared on 4 November 2026 as part of Amateur Gardening’s seasonal advice. Its focus is the maintenance of polytunnels and greenhouses after the main growing season, when plant foliage and falling leaves can accumulate on covers and conditions inside begin to change.
Stoddart says one of her polytunnel covers is at least 16 years old and still working well. That is her personal experience, not a guarantee of how long other covers will last; the report gives no product, installation or exposure details for that structure. Her stated point is that regular cleaning and prompt repairs may help plastic covers remain serviceable beyond a recommended replacement date.
Stoddart also says she leaves some lower foliage or ground cover to give wildlife, including spiders and ground beetles, an overwintering refuge, while keeping the plastic itself free of debris. The advice therefore distinguishes between removing material that obstructs or damages the cover and retaining some habitat at ground level.
“The more you look after your polytunnel or greenhouse, the more productive it will be for the longer term.”
— Kim Stoddart, Amateur Gardening editor
Limits of the Seasonal Advice
The report does not provide a measured estimate of how much cleaning extends a cover’s life or how often different materials need replacing. Stoddart’s 16-year example is specific to her own polytunnel, and the article does not identify the cover type, local weather exposure or repair history.
It also gives no fixed ventilation duration or temperature threshold. How long to open doors or windows will depend on the structure, weather and plants being grown; the report offers a general suggestion rather than a crop-specific schedule. Stoddart’s advice not to wash trays is likewise presented as her personal practice, with cleaning recommended if growers are concerned about pests or disease.
Tasks for the Coming Weeks
Stoddart’s suggested sequence is to clean the inside first, remove yellowing lower leaves and check the plastic for damage. Gardeners can leave some lower cover for wildlife while clearing debris from the surface of the structure. Outside cleaning can wait until more of the leaves have fallen, then be done with a soft method that reaches the roof without damaging the cover.
As winter approaches, growers can store reusable pots and trays and continue brief ventilation when conditions allow, while keeping doors and windows closed more often to retain heat. The report does not set out a later inspection date or a replacement schedule; ongoing checks and local growing conditions will shape what owners do next.
Key Questions
What should gardeners clean first in autumn?
Stoddart recommends starting inside the greenhouse or polytunnel, removing foliage stuck to the plastic and wiping surfaces with a hose spray, sponge or soft brush.
When should the outside of a polytunnel be cleaned?
She suggests waiting until most leaves have fallen, since leaves can continue to accumulate on the cover for several weeks. She describes using tied bedsheets with a helper to reach higher areas.
Should pots and seed trays be washed before storage?
Stoddart says she usually empties and shakes containers rather than washing them. She recommends cleaning if a grower is concerned about a particular pest, disease or eggs.
How can growers balance heat retention and airflow?
Stoddart advises keeping doors and windows closed more as temperatures fall, but opening them briefly a few times during the week when possible to allow airflow.
Does a 16-year-old cover mean polytunnel plastic lasts that long?
No. Stoddart says one of her own covers is at least 16 years old and still working well, but the report does not present that personal example as a typical lifespan or guarantee.
Source: amateurgardening.com
