They are about 10". What is confusing is the problem started to appear before I starting any nutes. I have only fed then once since and they sure semed to love it. The only things I can think of soil too hot (thought I saw issues with soil earlier), transplanting, starting CalMag. Light was at 22" but raised it to 24". But a light burns plants at top first? The other plants look just fine.Both those soils have lots of heat in them but they're great if the plant doesn't burn up when it's young. Hard on small autos. How big are your plants? Those fans are all super green, so it sure looks like nutes.