Afghan-joining panels & blocking?

I FINALLY finished the last panel of an afghan I’m doing for my Grandma BUT I am not entirely certain how to join the darn things. The pattern is old & pretty vague. Basically it just says to join in the back of the work.

  1. Do I join using whip stitch, singe chain crochet, or what?

  2. I have never had to block anything so I don’t really know if I need to block an afghan before joining the pieces. What do you think? Can I join it, wash it, & then gift it or is blocking a necessary evil?

Thank you!!!

I’d use the edge-to-edge stitch. If your yarn is machine washable, then I’d just wash it after putting it together.

Thanks for the quick response! You are fantastic!!!