This book is has been research by being in marijuana gardens since 1974, way before weed became in demand. I have seen good things come of it, and of course the bad. Now it seem's it may or may not be good enough, only because some grower's take for granted of not only the money involed, but to hurry up the growth of the bud's by putting to much, of what i would call fast grow dirt. So once again this book is not on how to grow, but the hard time's you may endure in doing so. Please do in joy.