The first frosts have already arrived in parts of the UK, which is your sign to get tender plants under cover before they succumb to the ravages of winter.
If you haven't already done so, check your greenhouse heater's working, that automatic vent openers are still operating, and clear out cucumbers, peppers, aubergine and chilli plants which have been fully harvested.
As the weather turns cooler, close up the greenhouse in the early afternoon to trap heat, which will help to ripen indoor fruit. Keep dampness to a minimum and ventilate when possible to move air around the plants and keep them healthy.