black

Hi there, I'm sitting a friend's plants, and I noticed that they have these weird growths on the main stem and the base of majority of the branches. The best way I can describe them is like small shells; maybe cacoons. They pop when I push against them, and the inside is a whitish-brownish...

I am thinking of taking an old locker and putting some plants in it, and putting holes in the top so the plants can get air. do you guys think that would work. Also is there a UV light that is also a black light, and if so can weed grow under it?