look up perma-nest trays. They are thick, long lasting and come in a variety of sizes. I have been using them for decades

Personally I wouldn't use any Jiffy tray, there are so many others that are stronger than those.

Thanks, I had never seen those perma-nest trays before.

They are really nice. Get the UV stable if you put your seedlings outside for any reason, like hardening off.

We we will definitely need UV stable. Every month here has a streak of days where plants can be left outdoors and often the flats will go out to a cold frame. Thank you.