Depending on the type of plants you grow, it helps to know what the humidity of the room is before adding any helpers such as extra humidity or heat.
These handy little hygrometers will measure the temperature AND humidity in your room, so you'll know what your room needs with just a quick glance!
We use one in every room that we house plants in (basically all of our rooms!).
Comes in black or white, with included battery.
45 x 45 x 14mmD