Lots of variables. Hydro or soil, temperatures, nutrients, strain, how close the light is, the plants genetic makeup, etc ...

8 to 10 weeks for the White Widow is for when they are grown in the best enviromental conditions and the genetic makeup of the individual plant it's self is also a big factor as well.

2 to 4 weeks to really get going in the flower cycle. Assuming all is good with your grow your should start to see much improvement over the next 3 to 4 weeks.

Good Growing!