Sowing times - when is best?

I have a number of seeds to sow, and my experience so far is that I get the best growth (germination and size fo seedling at end of the year) from seeds sown in March and April. I grow in 5cm pots, sealed in clear polythene bags, in a heated propagator in daylight and with extra lighting (4 x 25w energy saving lights at about 45cm height above seed pots).
This may just be my particular growing conditions, but I'd be interested in what other people have found.

Has I grow a lot of mamm's from seed I normally start after Christmas, but this year the first batch was sown on 30-11-08. There were 50 lots from the UK Mamm Society, Mesa Gardens and Cactus Heaven. The 50 lots were a mixture of speices from across the genus but members of the Ancistracanthae gave the best germination results plus 3 lots of M.tetrancistra SB 691, LZ 454, LZ 665. Only 4 lots failed to germinate.
I find that by sowning so early in the year you do need to give the best possilble amount of light. At the momment (and for the last 3 years) I use a heated electrical propagator , placed on the staging, in the brightess part of the glasshouse, althought I am thinking about getting a second heated propagtor and to start the seed sowing later in March.

Tam.

Interesting, Tam. I think you are right about light, and I do worry that when my greenhouse is at 5C over winter that maybe the propagator isn;t as warm as I'd like it to be. But that's a good germination rate - I'll look forward t hearing how the tetrancistra do in a year or so's time. I've found germination quite easy, but eeping them is another matter altogether. Now I have one on graft as well as the seedlings.