I’ve recently been left with 5 mid-late veg, feminized AK47’s as my housemate moved out rather abruptly last week. He was managing the grow, I invested the money for the setup, we were splitting the harvest (we had just harvested our first autoflower crop of GSC’s 2 weeks ago).
While I was watching from the sidelines and reading up quite a bit on basic growing guides, my friend was doing all the work and I wasn’t actively managing anything. For example, I’d read a bunch about managing EC and how this was an important factor in producing healthy plants.
His feed schedule and approach to measuring EC had always seemed a bit off to me - he was only watering in coco once every 2-3 days - and the plants all appeared to have some form of nutrient problems. One I nicknamed The Leopard because it had a bunch of pale yellow leaves with dark spots, and another was pale green.
Anyway, I took them over 5 days ago and after the first feed the EC was way too high - up in the 5s, 6s and 7s in some cases, indicating nutrient lockout. I double checked EC meter was calibrated correctly and it is, and it’s a Bluelab EC meter so it’s good quality, so no problems there. I flushed the plants, increased fertigation frequency, and dialed in my EC inflow, and while every 2-3 feeds it reads within the +300 range, it continues to blow out daily, up into the high 2s/low 3s.
I’m so confused, and although the plants appear to be pretty healthy, I’m worried they are going to take a turn for the worse.
I’ve read so many guides on how to manage EC, but I really need an expert to tell me the exact formula for managing EC inflow. Most guides, and my feed chart, says it needs to be between 1.1 - 2 depending on the stage, but then I’ve read guides saying things like
"EC of drained water – original EC = excess EC
Original EC – excess EC = EC value for the next watering"
Should I be mixing up a nutrient solution with EC between 1.1 - 2 every time, or should it be lowered/increased based on the reading of the run-off from the previous feed?
Thank you so much!