I think the rule of thumb is to germinate the seeds in darkness, but get them under the lights as soon as the seedling pops through the soil.

Mind you, for me darkness just means "not under the lights". I don't put them in a closet or anything. But you do want to cover them to retain moisture, and check them daily so that you can get them under the lights the minute you see the seedlings pop up.

Here is a link that might be useful: my blog

There is no conflict my friend. When you sow the seed you cover it with 1/4 inch soil and this created darkness. When they sprout they need light 24/7. You give them that much light because they don't see the sun. I read in a book that 24/7 light under flourcent lamp is barley equal to one hour in the sun. As for heat as soon as my seeds sprout I take them off the heating Mat. By this way they grow short and fat (stucky) as opposed to very tall and thin on the Heating Mat. I learned that from some books and It works for me.

If you plant your seeds direct in the garden,climate permitting, you automatically get the fluctuating temperatures Park recommends. Many seeds will germinate much better with these conditions. Many use the "winter sowing method" which works, but the seed germinates when the conditions are right for the seed, not necessarily for the gardener. Al