OK, resolved. The Swiss Chard guess is correct. I looked around and found sprout pics. This one: https://www.onehundreddollarsamonth.com/growing-vegetables-in-a-greenhouse-spinach-lettuce-swiss-chard-strawberries-and-tomatoes/ Interesting because that is about the size I have to grow in. I like the trays, I have been thinking about doing something similar but out of cedar fence picket for my enclosure.