If you're not using a heat source you can just let them sit for at least a month. A few years back I had a marginal amount (about an ounce of dried Mt. Hood, I think), in a little drying tray I made. They were rigged up to sit such that the exhaust from my dehumidifier was blowing on them and I forgot about them. About a month later, I wanted to dry hop a beer and headed over to the part of the cellar where my hop freezer and the dehumidifier were located. For some reason I happened to look over at them and decided to grab a handful and see what they were like. After a quick rub~n~sniff, in the keg they went. First time I ever dry hopped with Mt. Hood and will do it again (if they ever produce - not a happy variety at the B-Hoppy compound). The aroma was wonderful. I will say though that that part of the cellar is pretty dark and the temp usually never goes above 70 degrees. All in all, I'd say you're good to go!
"Neil & I would've tweeted from the moon if we could have but I would prefer to tweet from Mars. Maybe by 2040" ~ @TheRealBuzz, Buzz Aldrin 11:20 PM - 04 Jan 13