Need help deficity k or p?

If you can provide more information, like your nutrients, dosage, ph, EC, people might be able to give better help. It's hard to know for sure just off a picture alone

That looks more like an early nitrogen (N) deficiency rather than phosphorus. It’s common when the plant switches to flower it starts using stored nitrogen from the lower leaves. Add a bit more N in the next feeding, and increase your PK slightly (a bloom booster helps). Potassium deficiency usually shows with edge burn or rusty spots, not uniform yellowing like this.

They probably need a little nitrogen help, especially in the first try weeks of flowering!

Diaries really help to analyze what's going on so we have a better clue with what you have been doing and what could have started this. It's not always nutrient related when your plant is looking sick. This plant has been stressed for awhile now, the whole plant is yellowing.

are u sure his tap water doesn't have plenty ? ur advice could actually F up his plant... 👇😤

hey 👋 After flushing, be sure to use a flowering fertilizer, not a vegetative fertilizer, in smaller doses or 1 out of every 2 waterings. Also add 2 ml of CalMag per liter.

overfed flush asap and feed anew