Houseplants
Reduce watering of houseplants as the days shorten and growth slows.
Stand tropical houseplants on trays of wet gravel to counteract the drop in humidity when the central-heating comes on. Grouping them together can also help to create a more humid microclimate.
Pot up prepared hyacinth bulbs if not done last month. This way you will have them flowering for Christmas or New Year.
Plant up containers with Hippeastrum (amaryllis) bulbs for a New Year display.
In the greenhouse
Sweet peas can be sown early, in the glasshouse, for next spring. Keep and eye out for mice digging up the seeds for food.
Remove any shading paint applied earlier in the season, in order to maximise reducing light levels late in the season.
Greenhouses can be insulated using plastic bubble wrap. This will cut down the heating bills for the winter, but do make sure to attach the polythene in such a way as to minimise the amount of light blocked out by strips of tape etc, as the wrap itself will reduce light levels somewhat.
Check that the greenhouse heater is still working. Get electric or gas heaters serviced if necessary.
Ventilate greenhouses and conservatories during the remaining warmer days, but reduce ventilation once cooler, gusty autumn weather sets in.
Damping down becomes unnecessary as the month progresses. It is best to water or damp down the floor earlier in the day, so that the greenhouse is dry by evening.
Pest and disease watch
Dampness during the cool nights could be a recipe for fluffy grey mould (Botrytis) and damping off of seedlings.
Check and pick over plants regularly, removing pests, yellowing or dead leaves and faded flowers before rots develop. Slugs are often found lurking underneath pots.
When bringing plants inside, check carefully for pests and diseases they may have picked up in the garden, particularly red spider mite, mealybug and scale insect.
Unhappy looking plants can always be tipped out of the pot to examine the rootball for signs of over- or underwatering, or for soil-based pests like vine weevil.
Clean the glasshouse if not done last month, to prevent pests and diseases from overwintering in nooks and crannies.
Take care when watering indoor plants, not to wet the leaves (although this is not a problem with foliage houseplants where you are trying to increase humidity around the leaves). They will take longer to dry out in the cooler weather, and dampness could promote development of fungal disease. It is also best to water in the morning, so that the plants have time to dry off before the cold nights.
