If I were to put two different tomato plants var. in one earth tainer will they cross pollenate?

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I don't know what an earth tainer is but any two varieties grown close together could X pollinate.

HOwever, the results of that X pollination are not seen in the same year that it happens, only if you save seeds from X pollinated fruits and sow them, and if you aren't saving seeds for your own use then it really doesn't matter if X pollination occurs.

There's a good article on how to prevent X pollination if you click on the FAQ link at the top of this first page if indeed you do want to save pure seed,

Carolyn

Carolyn, sorry for the confusion but earth tainer is known on this board as the bootleg version of the Earthbox.