What to grow in your cold greenhouse in the winter. Depending on the temperature the seeds might be a bit slow germinating and the cutting might take a bit longer to root than normal
All best sown in pots ideally inside a small propagator within your glasshouse with some horticultural fleece on standby for the very cold night in the dead of the winter.
If the weather produces a warm winter then fungal diseases are going to be your main problem so remove all the dead leaves from the plants and general area to stop fungal disease spreading.
Plants from Seed
Salad leaves I aim to sow at least one 12cm (5in) pot of salad leaves every week and get two or maybe three cuts per pot. Right now, the hardier oriental brassicas, green in the snow, komatsuna, mizuna and red mustard can be germinated indoors and will be ready, depending on the weather, in around six weeks.
Mangetout peas ‘Oregon Sugar Pod’ stands low temperatures better than others. Sow four seeds to a 10cm (4in) pot. Pot on into 30cm (12in) pots when around 15cm (6in) tall and support with 1.2m (4ft) long twiggy sticks, or plant in soil beds.
Sweet peas I never get around to sowing in October, but I’ve often caught up by sowing in November, December or January/February. You’ll still get flowers weeks ahead of spring-sown plants.
Broad beans Sowing now produces young plants for early spring, planting either in beds (near the door so bees will find and pollinate them) or outdoors. Sow one seed to an 8cm (3in) pot. ‘Aquadulce Claudia’ is reliable.
Early-pull carrots ‘Amsterdam Forcing’ and ‘Early Nantes’ do well from late-winter sowings in a 30cm (12in) pot. By spring you’ll have tender young roots to pull.
Plants from Cuttings
Pyrcantha – in late autumn easy to root in pots from stem cuttings and will over winter
Skimmia Japonica – in late autumn easy to root in pots from stem cuttings and will over winter