I think if there was a time limit once it was opened it would say so somewhere, and I've never seen this. My dates usually say USE BY so that answers that question for me, but I guess all could be different. I would guess most are USE BY because that's the only hard, firm date. Sell by would be too open ended I think.
Well right now, my huge container is about half empty, the date is 2/06. So I plan to keep on using it, won't hurt me, and buy a new one when I get back from Scotland. No point in opening a new one when I won't be around for 3 weeks and it will sit in a hot house. Blah.
