as for the fertilising thing......the plants when they need to be fed with ferts they show it to you.....in this case look for the first set of leaves the plant grew from the beggining....yeah, right, the two round leaves, right at the bottom of the plant....if they are green then the plant has everything it needs, when they start getting yellowish this means that you need to add nitrogen as the plant it consumes what is already stored in the leaves and thus the yellowing on the leaves alerts a nitrogen deficiency....normally the soil that comes already fertilised is good for most of the vegetation cycle....i completed my vegetation using ferts 2 times only within the 5 weeks that took to get into 12/12.....when you think it's time to apply ferts go low....use 1/4 strength for the first time and build up to full strength slowly....more or less in a normal situation you will be using them one time every week or like every 2-3 waterings depending of plant growth and needs....remember that overfertilising DOES NOT make them grow more.....that's all i can think of right now.... take care and good luck with your grow....post some pics when you can
and remember, look at your plant carefully, it can tell you what it needs....watch the leaves....