Your plants will adapt to the growing environment by making larger type leaves to deal with larger amounts of humidity/heat and produce thinner leaves for lower humidity so if your plants have been brought up in one type of humidity then a change will have those kind of affects with the exception of switching over from veg to flower where the plant kicks into a different part of the growth cycle and then can adapt to a different humidity in a favorable manor because you are helping the plant to take a step in a direction that is already heading, IE lowering humidity to assist with the natural process of starting to create THC/resin for breeding/survival/photosynthesis.
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Thanks KP
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