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Week 5 yellowing, N def or natural fade?
Running a photo strain, week 5 of flower, and i'm seeing the lower and mid canopy leaves going yellow and dropping. Not a rapid spread, just kind of a slow creep upward over the last week. My current N input is pretty modest at this stage, around 50 ppm from calcium nitrate and a touch of potassium nitrate, because i usually back off N mid-flower.
Here's what i'm unsure about: at week 5, some yellowing is expected as the plant cannibilizes older growth. But i also know that if the fade is moving into the mid canopy this early, it could be the plant pulling more N than i'm giving it. The color is a uniform pale yellow, not really blotchy or interveinal, which to me reads more like mobile nutrient stuff than a lockout.
For those who've dialed this in, what's your read? Is week 5 a reasonable time to see natural fade kick off, or would you bump N back up a little and watch for a response over 3-4 days? Trying to decide if i should push my nitrate input up to maybe 80-90 ppm and reassess, or just let it ride and trust the process.
2 Comments
Week 5 mid-canopy creep is the part that would make me tweak, not the lower stuff. Lower leaves yellowing in week 5 is pretty textbook, but when it starts climbing into the mid section uniformly like that, my experience says the plant is running a little hungry.
The uniform pale yellow without any interveinal pattern is the tell for me too. That reads mobile, which means the plant is actively pulling from older tissue. That's not "natural fade" exactly, that's the plant solving a deficit on its own.
Where i'd push back a little on the thread consensus (if people are saying just let it ride) is that "trust the process" can sometimes mean watching the plant eat itself when a small correction would've kept more green on the canopy into weeks 7 and 8. More green leaves working longer usually means the terp profile finishes with more complexity in my experience. Plants that fade too hard too early can finish a little flat in the nose.
Bumping to 80 ppm N and watching 4-5 days seems like a reasonable middle ground. Not slamming it, just lifting the floor a bit. If the creep slows or stops, you have your answer. If it keeps going anyway, then you know it's not the nitrogen and you can start looking elsewhere.
The 80ppm bump is reasonable but i'd check runoff pH before touching the feed. Seen plenty of cases where the plant looks N hungry and its actually a lockout situation, you add more and nothing changes because the roots cant take it up anyway. Rule that out first and then adjust feed if pH is clean.
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