jiffy pots are a curse, you should tear the cloth before it gets to be a problem
also ive seen MG kill seedlings, i hope your lucky, also that you didnt spend money on your seeds
heres what you should do next time. if youve got those jiffy pots still tsart a germed seed in those for a week of so. then tear the cloth and put it in a cup cup or small pot with soil. if your going to use the MG then pull all of the little green nute balls and you'll be fine. around 2 weeks later or when the plant out grows the cup transplant it into a pot with full strength MG
good luck man