Low Temperatures in the Grow Room

Cold Grow Room

Maintaining your greenhouse or grow room temperature at an optimal rate during cold weather is important to help keep your plants healthy and productive.

Very low temperatures can cause unnecessary stress to plants which can stunt their growth.

Most plants usually do well in 60 degree (fahrenheit) weather but if temps get any lower you may need to intervene.

cold grow room


In a small space like a bedroom/shed/garage or a growbox, installing insulation is a big step towards helping to keep your grow room temperature optimal.

Grow Room Heat Source

Your heat supply can come from your ballast/s and the lights during the day, but you may have to take it a step further and add a portable heater and a thermostat (if your heater doesn’t have one) if the grow room temperature drops too low at night. A fan to push the air around would also be a good idea.

If you are growing in larger space like a greenhouse, you may need to add a heating system. As a side note, I recently read about a low cost/low tech method of lining your greenhouse with about 5 ft. of compost. As the organic matter decomposes, it gives off heat that helps to keep the greenhouse warm.

Make sure you’re venting your space to prevent too much humidity from building up. To do this, you can use a dehumidifier attached to a humidity controller . (optional)

Grow Room Water Temperature

Maintaining the nutrient temps above 50 degrees (fahrenheit) is also a good idea to help prevent unnecessary stress.
Placing a thermometer in the reservoir will help you to keep an eye on the water temperature. If the water gets too cold you may need to use a reservoir heater to help keep the the water temperature optimal.

Keeping the grow room temperature to stay warm will keep your plants happy and help to provide you with a great harvest.

Happy Growing!

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