IM new to all of this as well. I have a greeenhouse and started some impatiens and carnations. One advantage to early starting flowers is for early bloom. I know like zinnias can be sown directly. As far as veges go broccoli and cauliflower and other cabbage forms started early in the greenhouse will result in very early production. I also think have constant lighting will insure good quality stable plants.

It really depends what you want to grow. I have been winter sowing with great success for all sorts, but the main purpose is for perennials - it is the best for perennials for sure.

As for annuals, I am tired of having Cosmos and Marigolds (for example) only come to bloom in early autumn, so this year for the first time I will be starting such annuals under fluorescents (soon!). Maybe even a few veggies - as I also got tired of toms only ripening days before hard frost!

I am doing both as well. I WS my hardy annuals and perennials, but Grow under lights my tender annuals and veggies. James