I have read about some sort of water-resistant drywall that is used to frame bathrooms and other high humidity areas. Check into that. You can tack white visqueen plastic over that for good reflection (it's a heavy duty plastic that is white on one side and black on the other - I use it and it works great to reflect light and protect from splashes).

I use the washing machine trays too, but instead of perlite, get "eggcrate" at the home store. It's the white plastic grid stuff that they put over fluorescent lights in suspended ceilings. You can cut it to size with a strong shears or wire cutter. Then you just pull out the sheet, wash the pan, and you're good to go (I don't think I've washed a pan yet, though, it doesn't get very nasty). Supposedly the eggcrate can even go in the dishwasher if needed.

Sounds like a fun project and you've planned well - I'd like to do something similar someday in my basement. Keep us posted!

The eggcrate is a good suggestions but if you want the pebble type mixture, save the money on the coarse perlite and get small aquarium gravel.

The foam board sounds great and the cleaning should be easy with spot cleaning of an algicide, if needed. Flat white is the most efficient color for light reflection.

You can also use an algicide in the trays to keep the water sparkling clean and the water evaporating will definitely help with increasing the humidity. I only had to add the algicide (Physan) to my trays a couple of times a growing season. I only used lights about six months a year. The algicide did not evaporate with the water and I only had to readd it if I was neglectful and let the water totally evaporate.

Your set up sounds great for phals - good luck.

Brooke

I use an old door mirror set on its side behind my light area. Don't know if it helps or not. Probably could angle it better. But the price was right and I only have one long shelf to deal with.

Two products for walls; Wonder Board, a cement/fiber product, and Durrock (sp?), a very tough silica product, are water proof. They're usually taped and compounded like sheetrock for tile work but for your use I would suggest a waterproof caulking. Both products are grey. I assume they can be painted. There are specialty paints with high reflection capabilities. I've worked with both products (compulsive do-it-yourselfer here)and the later is easier and less messy to cut. Beware that your other suggestions are usually water resistant and not water proof.

I wouldn't use perlite. It floats and would get nasty quickly. Plus being white, you would see it getting nasty quicker. I would use clay pots with the open end up and put a wire grid over them. The egg crate would work but i think it is too brittle/fragile. Drop one pot on it and you'll be replacing it. Clay pots will wick up moisture, they're cheap and easier to clean, and readily available. With the open ends pointed up, any air flow over the large surface area will boost humidity better, I suspect.

I would use something cheap but durable for the walls, paint them with white marine epoxy paint, and affix some plastic coated hardware cloth or other type of wire grid over the panels. That will provide endless spots to hang mounts which you will undoubtedly, eventually, acquire in large numbers. You can also use the wire to hang additional lights or fans, or to hang pots higher up so they're closer to the lights, if needed. It will allow you to use your vertical space.

Ventilation will be very important, especially if you have very cool and humid conditions, as most basements would. Sounds like a fun project. Post pics when applicable, please.
-MB

Try looking on FarmTek (Farmtek.com) for a bright, white, washable product called Polymax, which comes in sheets, and also for their Tekfoil insulation - it's silvery, reflective, with "bubble-wrap" layers. They also have a greenhouse section, so anything there might help, including grates for shelving. Their prices are usually VERY competitive.

Thanks to everyone who responded today and for all the good advice, links, etc. I'll probably end up using an amalgam of all your suggestions and I'll be glad to post pics when I get it done. This is a really helpful forum!

Best,
-geoff