Leave damage after flush. P deficiency?

[athos]

Hello there.

I have several autoflowering strains outdoor between 65 and 75 days old from seed. Yesterday I flushed them. Today morning one of them, a White Widow XXL 71 days old, which looks like it still has 2 or 3 weeks to go, presents dark brown spots on leaves, which weren't there the day before, it looks like P deficiency, should I feed it?

 

[Heavily Medicated]

Looks to me like Mg def, but P can give wide def symptoms. You did not say why you just flushed, I am assuming you were doing the near harvest cleansing flush, if that is the case, it's working. The purpose of a cleansing flush is to wash nutrients out of the medium and force the plant to eat itself to finish up. This whole theory is a highly debated subject. Some swear you have to do it to get smoother, better tasting smoke, others insist it is not neccessary at all and just ruins the natural taste of the plant.

 

[Waira]

...Hmmm, this happened right after flushing you say? ...atypical presentation of symptoms-- no yellowing, and the speed of it happening makes me wonder about P defc.,... I see the rain on the plastic,.. is it cold at nights? It's rare, but I've seen cold drafts on leaves cause very similar symptoms, overnight basically,.. this is mesophyll cell collapse, which is noted by the sunken necrotic patches,...