Plant out or harden-off at how many leaves?
I started my tomato seedlings and others quite a bit later than usual this year. Normally at this time of year, I'm hardening off fairly sizable starts in anticipation of planting out in a week or two at latest. I usually start planting out tomatoes no sooner than May 19th, no later than June 2. Works out fine in my zone.
Right now my tomato seedlings have only two sets of true leaves each. They are still indoors.
Is it too early to start hardening them off? Is it too early to plant out if they only have two or three pairs of true leaves?