There is nothing better to lift your spirits on a dull gloomy day than to sow some seeds in the greenhouse. Although it is still too early to sow most crops there is still lots that could be sown especially if you have the protection of a greenhouse even if it is not heated.
I have not heated my greenhouse for years now and have not had any problems to date yes I have to sow a bit later for some crops. But that dose not matter as the crops always catch up eventually but I have noticed that the harder you grow the plants the better they perform when you plant them out. But at this time of the year there are some crops that once I have sown them I bring them indoors and place them on the window sill to get a bit of heat. Tomatoes, chillies and aubergines all need an early start and a bit of heat to get them off to a good start so they are all put on the window ledge. but brassicas, lettuce, peas are quite happy being sown on the unheated greenhouse if it is going to get really cold I just through a bit of fleece over them for a bit of extra protection. I also start off a few pots of salad leaves, radish and first early potatoes in the greenhouse so we get some early crops before we start cropping outside. It is forecast to rain again tomorrow but hopefully the weather man will get it wrong again and we have a nice dry day so I can do a bit more outside.