You've got the right idea with the particle board, I used a cabinet and I want to be able to put the shelves back in and use it again one day so I don't want to cut any holes in it, but I am having a heat issue, at least I think that's what I think it is. Up near my main cola, which is quite shabby compared to the rest of the bud sites, my leaves surrounding the buds are folding downward. So a homemade grow box is a great start. I started this little project on a shoestring budget and it costed a lot more than I expected and I'm still not quite what most would consider up to par on my lights. But it has been a fun adventure and it was worth every penny since I am now rooting my second clone from the blueberry. So at $125 a quarter for the BB from a dealer, I am growing 3 plants of my own that I plan on collecting at least an ounce each from and easy math says I'm saving bank rolls, and could make some bills too if I planned on selling it but I don't think that's the way to go for me. But back to advice, sorry i'm a rambler, I would invest in some more light I forget the actual wattage but I got a 300w replacement for $20 at lowe's, and also what kind of nutes are you using or plan on using? Also a great bit of advice is experiment experiment experiment. I think I'm going to try a compost grow with my latest clone that I topped at it's node.
Anyways, here are some pics of the budding bb with the possible heat issue, and the topped clone that I think is developing powdery mildew (read in Cannabis Culture this is an easy fix but they didnt describe the fix) and also some pics of the latest clone that I have in a bottle of water with a few pellets of rootblast 2-1-2. Same way I rooted last one. No gel, or cloning solutions.