Where is the most important location to take the temperature in my marijuana grow area: top, middle, or bottom of the plant?
There are really two spots that you should be worried about when it comes to temperature. The canopy temperature shows exactly what the marijuana plant’s leaves are experiencing. But, you should also measure the temperature of the soil to check what the roots are experiencing. For the most part, marijuana thrives when in the mid-70s F (low 20s C) for both leaves and roots. When the roots are cool, the leaves can withstand greater temperature increases and vice versa. For example, if the roots are cooled to 62F (16C) the leaves would thrive at a temperature of about 85F (29C).