Posted: 14/01/2013 at 15:38
Does your greenhouse have electricity? If so you can use electric propogaters to start seeds off. I have a cold frame in the greenhouse with a warming cable in it that I bought through internet. It doesn't use much electricity. I put seed trays in there. But I don't start sowing until March, as Geoff says, the light is better and the weather starts warming up. The other thing is that if you sow annual flowers too early and they get to a size that needs to be planted out but there are still frosts, you have to keep them in the greenhouse, re-pot them, feed and water them and they take up room. You can start off seeds on windowsills indoors too, either in a tray with a clear plastic cover or pots with plastic bags over them. I also use clear plastic food containers with clear lids.
I don't sow many perennials, I find it easier to buy a decent plant and take cuttings or split it. Annuals that are colourfull that I have grown from seed - petunias, rudbeckias, snapdragons, nicotiana, ageratum, ipomea, french marigolds, lavatera, salvias, cosmos, zinnias. You need to get a good seed catalogue like Thompson & Morgan or Suttons. You can look up the plants on Google. Something to do for the garden during the cold weather.