"Moisture is the essence of wetness. And wetness is the essence of beauty." -Derek Zoolander
Do your soil a favor and monitor it with this handy-dandy moisture meter! It has a built-in indoor/outdoor thermometer, and it has a programmable temperature alert. How cool is that? It's even wireless so that you don't have to sit right by your plants all day! Unless that's your thing. Then do what you gotta' do.
These require 4 AAA batteries, which aren't included. The temperature range is -4 to 158F and it transmits 100 feet.