Quote Originally Posted by Sjapp
If your humidity is around 20% or lower can it be bad for the plant? If it is I don't understand why it would be bad for the plant because the leaves don't absorb water do they?
From what I've read - and this could be biased information, so take it with a grain of salt - but humidity levels lower than 30% prevent the stomata on the leaves from opening fully (or at all) and reduce the transfer of C02 and other gases to the cells of the plant. Slow growth and symptoms similar to nutrient burn can result, but aren't always typical. If most other conditions are optimal, excessively low humidity may not pose as much of a problem. It certainly beats excessively high humidity any day.