[Greatgardens]

Zone 5b here... It is not safe to set out unprotected plants before ~May 15th. It was 36 F. last night. We've had some light, patchy frost several times in the past week. Supposedly this is about to change with a warming trend. I do have a cold frame which helps a lot on these cool spring mornings. I use LED/Fluorescent lights that take care of the early lighting. I like "pink" bulbs, including the T8 fluorescent tubes. I have poorer results with "daylight" tubes.

I plant micro-dwarfs (Aztek, Red Robin, etc.) about Feb 15th
Early dwarfs (Dwarf Arctic Rose, Dwarf Pink Passion) around March 7.
Other larger plant varieties around March 21. (regular Det and Ind and larger dwarfs)

In a good year, I'll have cherries from my micros in late May to early June.
Small slicing tomatoes from the Dwarf Arctic Rose, etc. by the 3rd week in June.
Main crop tomatoes start by around the second to third week of July.

And of course, so much depends on the weather. 2021 has given us a cool spring. I suspect my tomatoes will be around a week later than normal this season. And the varieties are so important -- the early Project Dwarfs can be started earlier because many stay small. Fourth of July does well for me here, but the early dwarfs can beat it by a week or more, since they were started earlier. Dwarf Arctic Rose is the earliest dwarf I've found. Dwarf Pink Passion is several days later, but produces more. YMMV, but this works well for me.

-GG