i think opuntias

I grafted my cactus (columnar cactus or san pedro I don't know exactly) with opuntia subulata a week ago, now it's getting cold, can I take it outside?

I didn't know we could eat Opuntia cacti. I grow the form called "kaynana dili" where I live (I think they call it prickly pear in English) I would like to try