keever, any tomato variety can cross, hybrid or OP ( open pollinated). All heirlooms are OP but not all OP's are heirlooms.

Please go to the top of this first page and click on the FAQ link and scroll down to the article on How To prevent cross pollination and I think all your questions will be answered. It includes picturs and bagging blossoms and all else tht I think you might want to know.

If not, please just ask here in your own thread.

Carolyn

I have tried saving seeds several times by bagging or specific blossom pollination and quite frankly, it is very difficult. I don't trust my own results.

My hat is off to those who do it, but unless they have VERY geographically isolated varieties, I have to wonder how true-to-type their saved seeds are.