Autumn gardening - November greenhouse

Snow generally slides off the corrugated panels of a greenhouse, especially if you are heating it, but should snow begin to accumulate, brush it off with a broom as it not only adds to the weight on the roof, it acts like a shade medium, cutting out all the sun that your plants need now. Insulate your greenhouse using bubble polythene. Choose grades made especially for greenhouses, as these contain UV stabilisers which prevent them from breaking down in daylight and all you need to do is pin the polythene to wooden-framed greenhouses while with metal models you'll have to buy special plastic clips that twist into place in the frame. In addition, use sheets of white polystyrene to line the glazing under the staging. This also reflects extra light back up into the greenhouse.

As the weather worsens you may want to bring your terracotta pots into the greenhouse, as they need a cool and dry place to avoid cracking from cold and moisture expansion. Plastic items such as pots and furniture which are prone to brittleness should also be brought inside. Metal items should be cleaned, primed and covered with weather-resistant matched paint.

Check that plants being over-wintered under glass are healthy and pick off discoloured leaves and dead flowers, which encourage diseases and of course make sure the plants are pest free - if they have any infestation you need to spray the greenhouse and possibly - if you are an organic gardener - bathe the plant in insecticidal soap mix. It's time to start watering plants more sparingly now as even a heated greenhouse becomes cooler and the plants put on less growth. Make sure there is good circulation around the foliage to prevent fungal diseases, pruning out very top heavy plants if necessary.

November greenhouse photograph by umjanedoan, used under a creative commons attribution licence