It’s a real joy to have a greenhouse where you can potter when the rain, snow and waterlogged ground make gardening outdoors impossible. Thankfully, there’s plenty to keep you busy in there and hey, it’s not long now until spring.
If you lifted and stored your dahlias over winter, encourage them back into growth by putting the tubers into trays of peat free multipurpose compost and put them in a warm, frost free, greenhouse. When the new shoots are about 7.5 -10 cm long, cut them off as near to the base as possible, with a sharp knife (a craft knife is perfect). Remove the lowest pair of leaves and make a clean, horizontal cut, just below the joint from where they were growing. A spare clean ceramic tile is a useful cutting surface. Dip the base in hormone rooting powder, knock off the excess and insert the cuttings, 2.5cm deep into peat free cutting compost. Water with tepid water, keep the compost moist and put the pot in a propagator at 18C, in bright light. They will take 3-4 weeks to root.
If you have space in the greenhouse border, a large pot, trough or even an old growing bag, why don’t you make an early sowing of radish? While you are in seed sowing mode, sow some mustard and cress in a small seed tray, sow sweet peas in ‘Root trainers’ or deep pots for ‘hardening off‘ and transplanting in spring; you could sow some Broad beans, too.
Plants like peppers, chillies and aubergines should be sown this month as they need a long growing season. The third week in February is ideal, mid-March is fine and the first week in April is the limit. They all need bright, warm conditions and constant temperatures to germinate, so if you are unable to satisfy their needs, buy young plants from the garden centre or from the internet later in the year. (It saves space in the greenhouse, too). Water the surface of a 10cm pot of seed or multipurpose compost with a fine rose, using tepid water, then leave it to drain for at least half an hour. Sow the seeds over the surface, six to a pot, then cover them with a shallow layer of fine grade vermiculite. Put the pot in a propagator or airing cupboard at 18-21C (64 -70F) and around three weeks later they will have germinated. Transplant into a 9cm pot of peat free multipurpose compost when they are large enough to handle, lifting the seedlings gently by a leaf and grow on in the greenhouse at 10-15C. Make sure there is enough space between the pots so the seedlings don’t become elongated in search of the light. Once the pots are full of roots but before they are ‘pot bound’ transfer them into their final growing position in a heated greenhouse, in 25cm pots of peat free multipurpose compost or growing bags. If the greenhouse is unheated, sow later and don’t plant them out until May. Happy greenhouse gardening! Stay safe, Matt.