That is the big question! Now assuming you don't live on a mountain, like me (had snow a few days ago), and are in a warm climate, the best answer is the bigger, the better! When it comes to size, anywhere between 6 inches and a foot is fine. You want them big enough to stand the bugs and wind.

In regards to hardiness, cannabis is much like tomatoes. Are your neighbors putting out their tomatoes? Add about 1 or 2 weeks to the date you see the grocery store tomato plants, to be safe. (Grocery stores are all about profit- frozen plants = no $)

Where I live, I have seen snow in June :wtf:- we are expected to have light snow tonight. Here, I wouldn't put out any of my plants until sometime next month or even May! I just planted my snow peas. Hope things are better in your area! - Granny:hippy: