What Is This?

Look at @Seamaiden thread helpful charts

Flush flush flush .

Colbgro said:

My plant was doing fine but I drenched the roots in humic acid and 2 days later this! They are in coco so Im not ruling out a deficiency

Click to expand...

Looks like possible K+ to me. Using humic acids means you must reduce the amount of fertilizer you're using or you can cause burning and other problems. Coir is high in K already, so you made it more available when using the humic and caused a bit of a toxicity.

Of course, this is just my opinion on the matter. :)