The question of when to start flowering is very different between growers. I just vegged for like 9 weeks and my plants became so out of control I couldn't manage them anymore by the time they budded. The good news is, the longer you make the plant stay in a vegative state, (24/0 light) the bigger the plant will be when it's done flowering. You can start flowering as soon as the plant is healthy, which means almost right away. But it won't grow to much more in a flowering stage. I suggest you veg it to about 2/3 of the size you want it and then flower it. I've also heard both way of putting the sprouted seed in a plug; upside down and right side up. Both were successful. The shell will fall off.