I personally own Ed Rosenthal's Marijuana Growers Handbook and can attest that there is nothing that book doesn't cover! It is a great book to learn all about the cannabis plant! You cannot go wrong ordering it. I do not own the Cannabis Grow Bible, but maybe someone will post about it. I don't know the cheapest place to order, but Amazon is reliable and ships out pretty fast. As for the watering problems. Underwatering results in plants that will wilt. It is very serious and you will need to give them water quickly to save them. If they are underwatered, give them only pure water to revive them, fertilizers can burn them, since they will drink up the water you give them very fast. Over watering plants will make the leaves droop down, more so at the tips of the leaves. It is definately noticable!