Only three harvests in, and already I'm seeing some interesting data! I'm growing spinach, lettuce and mizuna for the growth rate project in two greenhouses. In greenhouse one the heat turns on when outside temperatures fall below 50 degrees. In greenhouse two the heat turns on at 40 degrees.
Recently, night time temperatures have been in the forties so the heat has turned on in one greenhouse but not the other. Consequently, the greens have grown taller and weigh more in the warmer greenhouse. Since there are only three data points I can't really make any real conclusions until more data is collected.