Mold? on soil, need help with first grow

Is it mold or "Santa's beard"? (Last pics)

Growing it inside an old freezer with no ventilation since mid november and it has been growing great apart from a few deficiencies that it had when first starting out, but they seem to have went away.

BASICALLY.

We've been putting some random supermarket fertilizer (granules) into water, mixing it and watering Big Bertha. (That's the big girl u can see)

The fertilizer would not completely disolve in the water and the left overs would drop on the top of soil(I know, not the brightest idea).

I think the leftover fertilizer turned into this(pic 3,4) hazard and I just want for some guidance.

BTW the leafs and the stem dont seem affected.

SHOULD WE just bulldozer off the top layer of soil and clean the plant with milk/water? Or do something else?

Help needed. Thank you for reading.

TLDR: I put random fertilizer on top of soil and it created mold. Read the post mf its not even that long