I started my seedlings indoors the last week in February. I live in Denver, and that gives about 8-10 weeks before I put them into the ground.
Seedlings at about 2 weeks
After 2 weeks or so I start bringing them outside and leave them in full sun on warm days or I put them under an old glass window on cooler days. On my days off, I sometimes cart them in and out a dozen times trying to decide if it is too cold outside or not. Its a wonder my kids survived my rearing. We don't use grow lights because frankly I'm afraid my husband will divorce me if I bring one more thing into our already crowded home. We have a very small bungalow and have to impose very strict limits on bringing "stuff" into the house. Anyone who has kids in school has some idea of what I mean. I could fill another home with stuff the kids bring home from school in a year.
seedlings at about 8 weeks
Anyway with all this carting of plant trays, it's no wonder that I look forward to the day when I can plant them and forget about them (OK, I won't forget about them until after the last tomato has been picked sometime in September, but I won's have to worry as much about them once they're firmly in the ground)
I know the advice of sage and wise old gardeners is to wait until 2 weeks after your last frost date to plant tender summer veggies. And every year I swear I am going to follow this advice. In Denver, that would be sometime around Mother's Day or after. It's best to follow this advice and avoid late frosts that could put an early end to a young tomato plant's career.
This year, April gave way to unseasonably warm days, with temps hovering in the high 80's many days. The plants were already so big they were out growing their little pots, top heavy and tipping over and they were drying out much quicker too. But I resisted the urge to plant. The empty beds, with their rich, dark inviting soil were calling, but I ignored them.
I faithfully carried my trays of seedlings in and out of the house every day, Finally, last week the weather was so hot I had to cover my cool weather veggies (peas and fava beans) with sheets to keep them from withering. The hell with science, it sure seemed to me like all danger of frost had past.
Last Saturday afternoon, with just 2 hours to spare before I had to work a night shift, I noted clouds gathering in the west. A perfect time to put plants in! They hate being planted in hot sun right? and we don't get many cloudy days in Denver, I needed to take advantage. I planted like a mad woman, embedding that lusty black soil so firmly under my finger nails and in the tiny cracks on my hands, they'd never get clean.
Later that night, while at work in a local ER, a patient came in hollering about how golf ball-sized hail had pelted him so hard he thought he had a head injury, not to mention huge dents in his car. "What a storm! Worst storm of the year!"
By some huge stroke of luck, my plants did not succumb to the hail, they did not even seem to notice. The next night the temperatures dropped dangerously close to freezing and my industrious husband found several tarps and poles and covered the beds.
Next year, I"ll take that advice.