Covered beds

We haven't covered any of the raised beds before, but I decided this year to cover a couple of them and see if it make a difference to what we are able to grow, particularly capsicums. The price of capsicums over winter is crazy so I want to grow lots of my own this summer and then slice and freeze them, but we haven't had much luck with them turning red while growing out in the open. I hope the greenhouse effect will help with that, as the green ones aren't as sweet.