So we had some issues color and roots on the 'Rex' Buttercrunch in ZONE C (Pre-empt). Through research and some phone calls we figured out it was over watering and possible pH imbalence. So we changed our watering from not continuous flows to timed ones at 15 min for every 4 hours.
Given the cool weather and cloud cover we have been having this made sense as well. So really change your watering practices to what the weather and plants are showing you.
Overall pleased with Zone C making a comeback for now. Stoked to see what the other zones produce. As of now pH levels are steady and will continue to measure daily and adjust accordingly.