Wish i could help out. I do NL every season outdoors. I keep things simple. Dig down 2-3 feet deep and 1-2 wide place proper soil . feed once and awhile let nature take over. somtimes i think trying to many different things to correct a minor problem cause more problems. I know a few of mine yellowed a little at bottom and in the middle. Due to heat this season. Also what is your water source. Outdoors when it gets hot. water sourses dry or slow up. that will cause a serious swing in your waters constistensy. aspeacally if in an area with higher iron or sulphur content. or areas with lots of limestone or what have ya. Happen to me. was giving them bad ph water and they showed. Just somthing to throw out there and to think about maybe. hope they work out. good luck and listen to rusty he know what he is doing . nothing he suggest to me every was wrong...