How do you preserve home made play doh?

Try and let it sit in a "moist" room, like your basement or such without a dehumidifier. It's gonna get hard no matter what you do but I'm thinking leaving it in a really dry environment is gonna cause to to harden quickly and unnaturally, leaving it rough and with noticable cracks. Hopefully a moist environment will slow the process and in doing so reduce the cracking and splitting. Other than that I don't really know how to help you =)