18 – Ideal temperature for marijuana plants

Marijuana plant temperature

The best temperatures to grow marijuana (not taking exceptions into account) lie between 20 and 25 degrees Celsius. If you go below this temperature the metabolism of the marijuana plant will slow down and eventually even block with a temperature that’s to cold. This is only a problem during the day, since photosynthesis doesn’t take place at night. It is wise to make sure that the difference in temperature between “night and day” is less then 10 degrees.


Above 25 degrees the metabolism accelerates what causes the marijuana plant to use more water, fertilizer and CO2. The level of Co2 must then be increased.

Always install a thermometer in the garden to check the temperature. Best is to get one that automatically keeps the temperature above a certain minimum.

To control the maximum temperature you should use input and outlet fans connected to an air pipe that works on a thermostat. The input fan should be placed in the lower part of the garden, where it can push up the warm air that’s eventually channeled by the outlet fan (preferably located at the top of the indoor garden).


A working input and outlet fan not only controls the maximum temperature, but also provides fresh air and avoids shortages of CO2.

Besides light, water, temperature and fertilizers the genetics of the marijuana seeds are very important. Bad genetics can never produce high quality marijuana. Visit my webshop for high quality marijuana seeds. And if you have any questions, please go to the forum or contact me at robert@ilovegrowingmarijuana.com. Don’t forget to like or share the article :)



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