I think it's like to happen a tiny bit, yea, but nothing tragic. The only way to get really bad stretching is to grow indoors with lighting that is not strong enough or too far away. Plus, stretching outdoors really isn't a problem; at worst, you have to stake up the plants, which a lot of people have to do anyway just from weight...

I assure you, clouds are the least of your worries. I can list about 100 things that you should be much more worried about: deer, police, smaller animals, insects, and so on. At this point, you have little to worry about. Tend to them, and let them do their thing.