Yes, I agree. I don't really think they are getting too dry. My humidity is between 55 and 65% rh. Humidity should be good.
It seems after transplanting into the SIPs, the plants go nuts, growing very quickly. But, it also seems after a while of this accelerated growth, the plants seem to start running out of nutrients and start lightening up. That is the stage I am at. I think my plants might be getting hungry. The lighting in my photos makes them look lighter than in real life, but they are all looking a wee bit light.