No experience from seed. Might try the Winter Sow forum.

In my experience if you give it rich, moist soil it spreads quickly. We have clay soil that I amend with composted horse manure + sawdust bedding just layering it 2-4" on top of the existing soil works well. I don't bother digging it in.

The 2 kinds of Ajuga reptans I've been using are the plain green leaved & the bronze leaf one. I started with a few plants in the fall '09 & now have hundreds because I keep moving it around anytime during the growing season. If I plant in spring 8" apart it's filled in by now. Spring rains do enough for it to establish here.

Did 2 spots again this spring & it's really nice around the stepping stones leading to the hose reel where it gets foot & heavy hose traffic. I planted some around the 4th of July and it seems like the ones dug from the other areas of the garden took off better than the potted ones.

In large pots it spreads & roots amazingly well. It looks great in hanging baskets, too as long as you give it shade for part of the day. Last July, I put 5 plants in a 10" cedar hanging basket & it's overflowing 12" beyond the edges even after clipping the runners from the edges 2x (in March the dead parts clipped off & in June I removed them for other garden projects). Another basket has Heuchera 'Caramel', orange blooming pansies, and the bronze ajuga in it. Ajuga takes over the whole pot if I don't dig some out spring & Fall plus clip some of the runners away. Last year I added an orange blooming calendula for blooms until hard frost.

Hope that helps with ajuga ideas.