Posted: 16/02/2013 at 09:34
I start sowing annuals in March. I have 3 little heated propagators and a cold greenhouse with a sand filled frame with a warming wire in it, where I put the baby plants once they are up. I've found that if you sow too early plants can go leggy from not enough light and unless you heat the greenhouse (expensive) you may lose plants if there is a very cold night.
But sweetpeas are hardy and it's best to sow them in autumn or February to give them a good start. But the young plants will need some protection, such as cold frame, cold greenhouse or porch.