I grew my last lot from seed in a soil that was 2.1 EC and everything was fine. Aplant will grow for a short time with no nutes,but if you dont feed by the 2nd lots of leaves,shes going japanese.
This is the phone# for Advanced Nutrients' Grower Support Hotline:
1-800-640-9605
Please call them and tell them you're growing in HYDRO (NOT soil, which has nutrients) and ask them when you should start the plant on nutrients.
IF they tell you something like, "when it has 3-4 new sets of leaves" please ask them how the plant can survive that long on plain H2O. Also, ask if there's any risk in giving nutrients to a young seedling and see if they mention anything about the possibility of burning delicate roots.
I have NOT called them in years, so this is not a setup and I'm truly interested in what they tell you, so please report back. I think it will be an interesting 3rd party perspective from people who's job is to assist cannabis growers.
Also, keep in mind, that their answers will be based on HYDRO. If you prefer, you can also ask them if their answers would be different if you were growing in soil, but I suggest using hydro because hydro has virtually no nutrients present (trace amounts if using tap water and not R/O) and we should be able to assume the plant would need feeding sooner in hydro.
Let us know what you find out!