Cleaning and Preparing the Greenhouse

Use the gap between crops to make the greenhouse ready for its next job. A useful reset combines cleaning with checking the structure, watering arrangements and the space your next plants will need.

By Simon Adams · Updated 25 October 2026

Choose a workable moment

Plan an annual clean, often in spring or autumn, or work between crops. If plants must go outside, choose mild, calm conditions and protect tender ones from chilling. With permanent beds or overwintering plants, work in sections rather than leaving crops exposed while the whole structure is emptied.

Clear first, then wash

Remove finished crops, fallen leaves, old twine and loose compost. Brush dirt from corners and equipment before washing. Clean glazing with warm water and a soft cloth; avoid abrasive tools. Follow the panel manufacturer’s instructions, especially for polycarbonate. Scrub staging and reusable pots, including hidden surfaces.

Do not lean on glazing or stretch over the roof. Use appropriate long-handled tools and arrange help for work you cannot safely reach. Make a separate repair list for damaged panels and fittings rather than letting the cleaning job turn into an improvised repair at height.

Check the water supply

Clear gutters so leaves and debris do not wash into stored water. Clean water butts annually and check their covers and diverters. If stored water smells, empty and clean the butt rather than adding chemicals. Use stored water frequently to keep it fresh.

RHS guidance advises against water-butt water for seedlings because it can carry damping-off organisms. Keep a clean supply for seed sowing and young plants. Clean the watering can too, rather than returning a dirty can to freshly washed staging.

Test equipment before the next crop

Open and close vents, check latches and test automatic openers. Run irrigation and inspect outlets for leaks or blockages. Make sure doors open freely and paths remain usable when pots and supports are back in place.

Keep a short list with three headings: repair now, replace before sowing, and check during use. This makes it easier to finish the essentials and avoids forgetting a small fault until plants depend on the equipment.

Reset the growing plan

Choose where seed trays, larger pots and beds will sit. Allow room for watering and reaching the back of staging. Keep the brightest space available for plants that need it, rather than filling it with spare pots and packaging.

Where a previous crop had a persistent pest or disease problem, identify it before replanting. Surface cleaning alone does not solve every problem in roots or soil. Use the relevant crop and disease guidance to decide what needs to change.

Finish with a practical check

Before bringing everything back, photograph the clear layout and note what worked in the previous season. Label the next crops and their intended positions. Keep a brush and a container for plant debris handy so routine tidying is easy between larger cleans.