Seed type aside, it will take you a few cycles of trial and error to know when your grass is peaking. their are many variables like watering and temperature which will override all at the end of the day. if your grass doesn't grow great, don't despair, as you can try less water or more, less seed or more, more or less heat etc.

if you notice the grass is starting to lose shape, cut asap, and next time a day or so less. it's a learning curve, but worth it. better than tablet or frozen crap.

be sure to make your potting mix is really broke up - not lumpy. it can make a huge difference.

and don't worry, if you get a bit of mold, it won't kill you - except maybe in canada.

happy growing, and listen to any advice from wheatenergy - he knows his ass from his elbow. advice in plain english - all you need to follow is common sense.