December 24: Break freezing ponds; clean greenhouse pests; start a gardening diary

Remember the fish at Christmas! Now we are into the colder part of winter, ponds will start to freeze over. If they freeze over completely get a saucepan of hot water and slowly melt the ice. Never smash the ice as the shock waves can kill the fish. One thing that works well is to float a rubber ball in the pond and when it freezes over take the ball out leaving a hole for gas exchange. If you have a pump in the pond you should remove it now or it will be damaged by the colder weather in January and February.

•Have you cleared all the remnants of the summer crops out of the greenhouse yet, if not now is the time to get it cleaned out and washed down to ensure all the pests are killed before next season. If you can find a sulphur candle to burn in the greenhouse that will see the end of any living thing in the greenhouse, including fungal diseases. Even if you are still growing in the greenhouse it is worth giving the glass a good wash to allow the maximum available light in.

•Take cuttings of perpetual flowering carnations and root them in a gritty compost, or mix equal parts peat and perlite or sharp sand. You could use a peat alternative such as coir – this will work just as well if not better. You will need to put the cuttings in a heated propagator to give some gentle bottom heat until they have rooted.

•Take care when watering as fungal diseases thrive in cool damp conditions found in a greenhouse during winter. Even plants in the house should only be watered when it is obvious they need it – and never feed over winter. Avoid getting water on the leaves as this can lead to rots and moulds forming, and fungal diseases like botrytis. Keep over-wintering Pelargonium and fuchsia rooted cuttings and plants warm and on the dryish, 13-16C by day dropping to 6- 8C by night. This should help prevent stem rot and grey mould.

•During the quiet days over the next couple of weeks get out and throw away all the broken pots and old seed trays and that are in good condition need to be sorted and washed so they are clean and ready to use again. I remember pot washing as one of the major winter jobs when I was a student gardener. If you find you have too many plastic pots why not take them along to garden centres that run recycling schemes? I know Notcutts run such a scheme.

•January is the time when allotments come up for rent. It is a very good idea to get one booked now so that you have time to cultivate it and plan what to sow before spring. I can think of no better way of working off the festive excess than digging over the allotment, and preparing to grow my own sprouts for next year. If you would like an allotment, contact your local council – most have several vacant plots, waiting for you to grow your own vegetables, flowers, and fruit.

•If you have not kept a diary of what you do in the garden week by week then make that your new year's resolution. It is so helpful to have notes on when you sowed things or what worked last year – and what didn't. You can learn a lot from your mistakes.