Anyone else feel like it's deja vu ..... all over again around here... 
 
Isn't the vernacular amazing!  New words added to the dictionary every year.  Other words disappearing from the language.  Still others acquiring new meaning over time.  Historical context lost and found again.  Multi-rooted words coalescing a common meaning over time. 
I just hope I don't get pulled over by the language  police again any time soon.    My plethora of citations will surely bankrupt me.   
 
Back to fertilization...
The point of my previous post was simply to say, that even when we use a control group and do a comparison, we need to consider the context in terms of our objectives.  Let's say treated plants (regardless of the treatment) grow much better than untreated plants.  Depending on ones objective, that could but a big contributor, make no difference, or even work against the objectives. 
I think experimenting with different methods, techniques, and products is great and lots of fun.  We just need to be careful what conclusions we draw from the results.