Nirvana ICE - Boron Deficiency or what?

[cflSam]

Hey all, long time listener, first time poster. I've got a 30 day old LST plant that's grown in FFOF with dolomite lime mixed in. Just this morning I woke to find a small burn on the top node. Over the course of the day it has progressed to this-

I know it's small. It doesn't show on any other part of the plant, just the very top newest growth. I've only fed the plant water to this point seeing as it was very healthy and the soil had nutes in it. Also the light has never touched the plant, so I'm sure its not that. Also the room is kept at 75degrees with a small fan hitting the plant so I don't think it's heat burn.

Is this a boron deficiency? Any suggestions on how catch this problem while it's still in the early stages?
Thanks all-

 

[bucktoothal]

Hello
It does look like a boron deficiency. Boron deficiency is usually caused by a high pH. Under acid soil conditions, boron is more water-soluble and can therefore be leached below the root-zones of plant Common products used for supplementing boron are Laundry Borax (11%B) or Solubor (20%B).