The freezer inputs cold air from the top down. If I have the temp probe in the foliage or at soil level, then that is where it should take it's temp. Running the ETC(Electronic temperature controller) I should be able to maintain my set temp at that level. As soon as it hits the differential set point (which is 6 degrees higher than the cooled set point of 74~) it will start to cool back down. So in theory it should stay between 74 and 80.One more thing.. I've read in a few places that the root zone should maintain 70° how do you think the freezer will affect your root growth?