The original SIP, the Earthbox , recommends covering the top. They suggest a plastic cover but part of that is because it was developed in Florida for outdoor growing so the plastic helps keep the rain from washing out the soil.Could this cause the plant issues I'm seeing? I know people have been covering to tops of the soil SIPs and seeing those feeder roots come right to the very top of the soil. I guess maybe an experiment with covered and uncovered SIPs is in order for my future.
We're having discussions in Gee's Gee Spot thread relative to top watering and pot moisture if you want to go check it out.