Most definitely, low humidity makes your plants drink more water and less nutrients. That creates deficiencies in the plant and salt build up in the soil. It is a bad thing all the way around. I don't know how big your grow area is but you can soak a bath towel or some large cloth that will hold water and put it in your grow area and that will raise it a pretty good bit. Like I said, depending on how large an area it is. If it is small, it could raise it 20-30% when the lights are on.