Sorry for the delay in my replies here and to my PMs but it's just that I get asked the same questions dozens of times. I have literally received over 100 PMs in the last two months and more than 75% of them have asked me the same questions (i.e. Where do you get your seeds? How much is your electric bill? What kind of nutes do you use? etc. etc.) that have been answered multiple times in this thread and would easily be found if they just skimmed through the thread and read just my own posts in it. I am really, really not trying to be mean and I mean this in the most polite way possible but please read the thread before sending me a PM with a question. There is a 95% chance that you will find the answer in the thread and it will take you no more than 15 minutes to skim this thread. Hell, it's only 13 pages long right now.
Rant over.
Now, I will answer the question about how long the nutes last because that is one I haven't received yet believe it or not. For a grow of this caliber (20 plants in 2 gallon pots, vegged for 6 weeks and flowered for 10 weeks that are watered every other day) a bottle of Grow Big would last for about 2.5 grows. A bottle of Tiger Bloom lasts for about two thirds of a grow and a bottle of Big Bloom lasts for about half of a grow.