Humidity -- Natural Solutions, and Questions

Hello,

I live in the southeastern portion of these fine United States -- within 20 mins of the beach -- Humidity is quite high all the time (can be in the 80% region often, and averages in the 70s). The question I have is, what is a problematic humidity level for plants in a grow box ( I have had mold on my bud before, horrible sight)? Should I confine my efforts to reducing temperature so as to lower humidity or both? And I have been doing some research on 'natural methods' as opposed to an expensive de-humidifier... please see below and comment on whether or not any of these is a known effective solution? Are any of these natural choices better or worse? Are any poisonous to the grow environment?? PLEASE COMMENT because my humidity issues will become catastrophic soon...


Rock Salt

"Damp Check Natural De-humidifiers":
http://www.allergyasthmatech.com/P/damp_check_natural_dehumidifier/164_0?s_cid=BIZ164

"Natural Wood Charcoal":
http://ionicspoint.blogspot.com/2010/12/natural-dehumidifier-charcoal.html

Silica Gel:
http://www.amazon.com/Grams-Silica-Gel-Pack-20/dp/B0038N30OY/ref=sr_1_7?s=electronics&ie=UTF8&qid=1327691738&sr=1-7

Depending on the size of you box kitty litter will help.

i'm working with a small grow box like 2 ft 6 ft --

and im currently running a 400 watt hps with 6 babies in it- -

Try a 4" tall bin. One that will fit in the space you have. Fill it half way with the litter and give it a try. Replace every week. You can dry it in the oven on low heat and reuse it or if you have a cat use it that way. And should help with some smell but not much.

Thank you warlock! I think I will try that. I need to get a small digital humidity meter / thermometer for my grow room --