A nice little Digital Min/Max Thermometer Hygrometer that includes an extra probe that allows for readings to be taken from two places at once. Don’t get caught out on the cold temperatures this winter. This allows you to monitor the environment both inside and outside of the grow room more closely. You could also use the extra probe to measure the temperature of your nutrient solution.

Unit itself reads temperature and humidity, 1.5m long probe only reads temperature. Easy to use. Records minimum and maximum temperatures. You can mount it on a wall or just let it stand on a desk. Digital Min/Max Thermometer Hygrometer with External Probe is not the most expensive item on the market but does work really well and is worth every penny.

Guide how to keep your room perfect is room temp 24C-28C with lights on, 21C-23C when lights off.

Aim for humidity 65%-85% in propagation stage, 60%-75% in vegetative stage, 45%-65% in flowering stage.

Also lookup the VPD (Vapour Pressure Deficit) chart for better understanding behaviour of plants in the grow room  based on the temperature and humidity.

• Temperature range -50 to +70 degrees C for the probe
• Humidity range 25 to 98% RH
• Dual LCD for temp and humidity
• 0 degrees C alarm function
• Accuracy +/- 1 degree C
• 1x 1.5V AAA battery