I've been occasionally watering lately with Epsom, but the older leafs especially, though younger as well, are still turning. Perhaps I should up the dose? Or would an increase in frequency be better.
HOw much are you watering? This happened to me when 1) i was watering more frequently and 2) when my soil was not drianing properly.. not an expert by any means.. just my experience.
I pretty sure it's not a watering issue.. they're growing in pots in the British climate so to fully explain would take up half a page. So in a nutshell they get watered when they wilt and the pot feels light, if however the pot is not light and they've wilted I will leave it until the morning before (possibly) watering.
Very nice chart :-) they've definetly had potasium deficiencies recently, however I used other signs to determine this. I didn't realise that this was also a sign.