I’m growing in FFOF soil and saw recently some holes in my bannana k and blackberry k. I’ll show pics of the problem and notes I take for feeding. ive only been using recharge and cal mag with every feeding. Keep in mind I sprayed them a week ago with peppermint and today with lavender, idk if it’s a pest issue.
I've only seen leaves like that for three issues, pest, ph issue, or sulfure. There could be more but those just what I've seen. I'd get a magnifying glass and take a close look at those plants, leaves top and bottom, branches, crotches, and also get a pH and ppm of medium.