Back in the late summer of 2007 I came across this method of sowing seeds. Can I just tell you that I'll never do seeds any other way again? I prepared ~20 containers and from that got more plants than I had room for. In fact, I gave some away and then put others in a make shift flower bed in the median (we live on a divided road). I put a few of the plants in to 4" pots where they spent the winter and are now waiting to be planted in to the ground. Oh, and the best part----all the plants (except for 1) that were wintersown were perennials.
Here's a picture of one of my flower beds. With the exception of the hibiscus and the clematis, all the plants were either wintersown, divisions from other plants or free (I swap iris with a friend of mine every year). All the plants pictured are perennials. I did not wintersow any plants this year and I wish I did!!! P.S. the 2 plant trays you see in the photos were plants given to me by a co-worker (she also got a few of the wintersown plants).