White on grodan cube! Mold?

I have white specs on my grodan cube! They formed over night I think. Is this the beginning of mold?

Thats right it is. Run a fan in them 24/0 and the mold should go , also reduce watering.

Will this sns 244 natural fungicide kill the mold without stressing out my babies?

try to do do natural things before going any harmful chemicals or any other things. click this link

Cut little squares of the black and white Mylar and place them on the top of the blocks, works a treat. It will keep them in perfect condition and you can re use them over and over. Its a little trick I have used for years

great advice from above, i do the same thing with my coco, ive cut small plastic circles with slits that fit lovely round my stem and cover my coco, help stops fungi growth and keeps them fungi gnats away,