Think of it like a science fair project. You want your control group and at least two more test subjects.
In my garden, my raised bed is the control group and my containers are my test subjects. The raised bed relies on organic mulches and fertilizers. No guano or any hydroponic concept of organics. By organics I mean I lay 2x4 lumber on the ground, grow out a cover crop, harvest the crop, then throw it down as a mulch, add layers of native soil, compost, and soil amendment, to build up the bed. Apply a light organic fertilizer in the start of the season and fertilize lightly through the rest of the season every 2-3 months. This method works for me with all fruits and veggies, and even the hungriest cannabis strains thrive.
Now in my my containers I can have more fun by trying out different cannabis specific nutrients. Last year was mostly an Advanced Nutrients run, this year is more of an X Nutrients run. Sometime I do two nutrients side by side, other times I use the same nutrient on all plants but change the soil or grow at a different pH range.
Easiest way for me to keep track is to keep a grow calendar, showing dates & rates of feeding, taking measurements of plant height & width and taking lots of pictures. I take most of my photos with my smart phone which automatically uploads to Google Plus. Just lock the album and disable the geotagging. Use the comments to enter any additional notes.
The only problem with testing is that your more likely to kill a plant during the process. Its nice to have a few of the same strain going at once, with some being tested and others getting your tried and true treatment.
