You will need a hygrometer to measure the humidity in your grow room. Hygrometers often include a built-in thermometer, which is great because you need them both.

Learn all about climate for growing marijuana:

• Create The Best Climate For Marijuana Grow Room
• Ideal Temperature For Marijuana Plants
• Temperature In Your Marijuana Grow Room
• Humidity And Marijuana Plants

More climate related terms:

Climate | Air circulation | Airtight | Charcoal filter | Extractor | Fancontroller | Fans | Humidistat | Humidifier | Dehumidifier | Heating