It sounds like he intended for it to be fed with guano teas, etc. I've never done that. I wouldn't feed GH Hydro flora series. That's for hydroponics and soilless (peat and perlite, without the other stuff). I've grown that way and can guide you through a grow if you really wanted to do it. But, for this grow, I'd either research organic/composted soil grows. Or, I'd get some fertilizer used for soil growing (houseplants) that is a 1-1-1 ratio (example NPK label: 8-8-8). Cannabis grows fine with that ratio throughout the grow. You don't need veg nutes and flower nutes. (It might help. But, you don't need it.). Gen Hydro has their "
General Organics" line. That would make sense for the soil you're using (if you like GH).
If it were me, I'd run down to Ace Hardware and spend $6 on MiracleGro "Tomato." It has an NPK ratio of 1-1-1.8. People hate MG. But, I've grown with this and it works fine. 1/2 to 5/8 tsp per gallon of water. (If I were you, I would get in the habit of measuring the runoff ppms using a TDS meter. If you overfeed, you'll see it in the runoff during transition or early flower. The PPMs will go through the roof. For me, 2500ppm is where lockout occurs. I try to keep it around 1800. Never above 2200. This saved me a lot of headaches dialing in the nutrient strength. I rarely measure it now.).
MG makes a "Bloom Booster" product too. You could bump the PK with that in mid- to late-flower. (Cut the "Tomato" amount in half, and replace it with a slightly less amount of the "Bloom Booster." MG's "All Purpose" is high in N. You can cut the "Tomato" in half and replace with a similar amount of "All Purpose" to increase N in veg. But... it will grow *fine* with just the Tomato ratio. Honestly, if I needed to bump N in veg, I'd add some fish emulsion. That would be healthier for the soil microbes than MG's "All purpose." (Something else you can do to help the microbes recover from your use of hydro nutes: add a pinch of ordinary kitchen sugar to the water. Not much. Less than 1/16th tsp/gal. That will feed the microbes.).