The humidity in my container is 40 at the top and just under 50 at the bottom. I live in california by the beach and it gets really dry. I was told to spray the container. So i mist it but it only helps for about 30min of 50% humidity. I cant be there to mist all the time. I added fir and it helped when I first added it but now its dry and the humidity keeps wanting to go to 40%, sometimes lower.

What can I do to raise humidity to 50-60% and keep it there?