Karen, I know exactly what you mean and I keep trying to find the perfect timing for starting my seeds. Last year I sowed my impatiens under lights on March 26, which was nine weeks before our average last frost date. I'd read instructions that said "sow impatiens seeds 8 to 10 weeks ahead of last frost" so I compromised on 9! Because our spring is slow in arriving this is a lot later than other areas of the country.
And I ended up with a lot of burly seedlings that took up all my space. AND I always sow lots because I like to plant them all over the garden. No exception with these impatiens; they were about 3-4 inches high when I finally dared to plant them out the first week of June. It's finally dawned on me that maybe the reason those seed-packets give such a wide range is that people's seed-starting environments can be so different. Duh! Light going on in brain! ;-) Since I use heat mats to germinate, cover with the BioDome to keep seeds moist, and keep the temperature as close as I can to the recommended one, maybe I WILL have faster germination!
So THIS year I'm going to start them later--maybe 8 weeks ahead (not a giant risk-taker here.)
By mid-July of last year they were providing some show in the shade border:
