Please help! Catt Seedling dropping leaves, PS.B brown and dry

[emmajs243]

First of all, thank you to everyone for your help. Although I haven't responded I have been reading! The past few days have just been tough...

Ok, so i am just so perplexed....I just kept feeling like I often heard seedlings need to stay warm and how they do better without a night temp drop so that's why I cut that back. I also heard seedlings shouldn't be allowed to dry and when they start producing new roots you should spray the root tips daily to keep them moist...so that's all I was trying to do. It's just in a 2&1/2" pot, one or two quick sprays to the media/root tips basically wets the entire top layer of media. Which I figured was ok because the top layer was always dry. But I never sprayed the actual plant, just roots/top media....is this wrong?? Is the nightly temp drop ok? Because I started with a 5-10 degree temp drop then swapped after hearing seedlings did better without a night drop.

The week this showed up though I hadn't been spraying. I mean maybe it was already present who knows....oh and also waterwitchin. When I actually water my plants, if a drop or two splashed in a leaf should I not dry it with a paper towel piece? It's less work for me, I just had read that you should dab it up. Also, the pot temp, with the heat mat, stayed in the low 80s. I have these little clip on thermometers that clip to the pots edge and the sensor sits right on top of the media so that's how I got that temp.

Next, after this seedling was lost, I decided to check the seedling that was sitting on the heat mat with this one about 6" apart. This one was transplanted to s/h and I've been so worried she was a goner because I broke a new root tip, her other root tip died and she stopped putting out new roots. Last week however she started putting out a new growth and I was so hopeful maybe she wasn't doing as bad as I thought....I unpot her to take a look and sure enough find this brown mush barely moving up a PB. So I go to cut it away before it destroys her and find that although it didn't present outwardly yet, all of Rhizomes and Pbs are also brown and mushy past every single eye. This one was especially heartbreaking because I had been so worried with the swap to s/h. AND she just seemed to be coming back from the swap...AND when I unpotted her, I found that many of her old roots had actually adapted just fine to s/h and were doing fine. I could see however where the roots attached to the especially mushy rhizomes were becoming brown and mushy from the base of the plant down....Her pots temp only stayed at the low 70s up to 75 due to the water too..which I wouldn't think would be too warm for a seedling? But sure enough she also had this stuff....

Ugh just one gut punch after another so please, will someone set the record straight? Sorry I'm just feeling like I need help knowing where the line is...Temp for seedlings? Night drop or no? Don't dry water on leaves? Don't spray new root tips? Don't keep seedlings slightly damp versus letting them fully dry? Oh and yes, airflow is good...fans are constantly circulating and an air purifier is running.

I know....lots of questions I just have lost both of My seedlings right when they seemed to be improving and it kills me. I just want to learn from this so it doesn't happen again.

Last thing....maybe this was the fatal flaw maybe not....I just didn't think twice about it until the night I lost my second seedling. Ok so what I didn't realize/think about...my humidifier. I bought it prior to the seedlings and it was set about 2.5-3 ft above the seedlings. Always running RO water and I do clean it regularly BUT when the seedlings came in I just had a nice isolated table space right there below the humidifier close to the plug ins for the heat mat so went with it. My thought/question, because humidifiers do kinda put out that super fine "mist" and it was being blown out 3 ft above them, do you think this could have been a problem I should fix? I know a cloud of mist is blown out but I figured because I could only see it fall like a foot, that it just dissipates very quickly...maybe not?

just thinking out loud while racking my brain on this....please, any advice would be greatly appreciated..oh and .also, any thoughts on adding physan to water like once a month and watering with it as a preventative measure? I know it can only do so much and culture obviously needs to change but do you think this might help ?