Am I right in thinking this is nitrogen deficiency?

[Proph]

This could be several things honestly. Is it an N deficiency? I highly doubt it. Many things LOOK like a deficiency. In my opinion, it looks like the plant is feeding off of those leaves to help keep other nutrients in balance. If there is a nutrient imbalance somewhere, the plant can move the mobile nutrients from the oldest leaves, to where the nutrients are needed... N, P, and K are all mobile, so the leaves that the N, P, or K is being pulled from, can look like any of those three deficiencies. But the slightly nute burned leaf tips on your plant tell me that your not under feeding. In flower, Nitrogen is the last thing the plant needs. Nitrogen helps make leaves. P and K helps to grow buds/flowers. Your plant is done making new leaves. True nitrogen issues usually happen in veg when the plant needs N the most.

What size pot are you growing in? If it's a smaller pot, then I would think that you can safely go to 1/2 strength without too much worry. We can't tell you whether it will work or not, but the plant can, and will. If the fading slows or stops, then you're on the right track.. If it continues or gets worse at 1/2 strength feeds, then there could be other issues.

 

[Frank56]

This could be several things honestly. Is it an N deficiency? I highly doubt it. Many things LOOK like a deficiency. In my opinion, it looks like the plant is feeding off of those leaves to help keep other nutrients in balance. If there is a nutrient imbalance somewhere, the plant can move the mobile nutrients from the oldest leaves, to where the nutrients are needed... N, P, and K are all mobile, so the leaves that the N, P, or K is being pulled from, can look like any of those three deficiencies. But the slightly nute burned leaf tips on your plant tell me that your not under feeding. In flower, Nitrogen is the last thing the plant needs. Nitrogen helps make leaves. P and K helps to grow buds/flowers. Your plant is done making new leaves. True nitrogen issues usually happen in veg when the plant needs N the most.

What size pot are you growing in? If it's a smaller pot, then I would think that you can safely go to 1/2 strength without too much worry. We can't tell you whether it will work or not, but the plant can, and will. If the fading slows or stops, then you're on the right track.. If it continues or gets worse at 1/2 strength feeds, then there could be other issues.

Hey Proph, thanks for the reply and the info. The burnt tips were more of a problem early-mid grow, relative to her time above ground (I was feeding when the soil wasn't depleted - that was the lesson I took with me).

On around day 28, I was still noticing burnt tips (very slight, nothing major), which would have been from feeding on day 24/25, so up until day ~36 she's had two feedings of 1/8th strength nutes. Queue day 36, and I have this issue, which to me, after your explanation (using P and K for the new buds), adds up to being one of the primary nutrient deficiencies (most likely not N due to her flowering as you said), especially because it's on the very bottom leaves only.

I'm growing in an 8L pot, which I imagine is on the small side, so going to move to half strength today - she's due a watering any time now really (conveniently). I usually give her a litre of water.

On a side note, and a somewhat related note at the same time, would you recommend the inclusion of bloom nutes at this point given her evident need for P and K? Or would you recommend waiting for the stretch to finish? She's adding about 1/2 - 3/4 of an inch vertical growth a day atm.

 

[THE BEAR]

Yeah I thought so, I've done a lot of research before plunging into this world, but it's always different when you're doing it for real... always second guessing, which I guess isn't a bad thing!

I'm definitely going to ditch the grow nute, and try fish mix next - it seems to be one extreme to another with it. You either burn, or underfeed. I'm going to up the feed as you suggest, but air on the side of caution and go with 50% strength and see if that stops the spread of discoloratio'n.

'Glad' to see others with similar issues using the same setup!

The fishmix is supposed to be good stuff but have yet to try it

 

[Frank56]

Gone ahead and fed her with 1 litre of water.

- half strength veg nutes (1.5ml)
- half strength bloom nutes (1ml) - first time using bloom nutes on her.
- 1ml Alg-A-Mic
- 0.2ml CalMag

Will report back in a few days with results and hopefully help others who come across this (if it fixes the issue!)

 

[Frank56]

Ok, update after 48 hours.

The issue did get worse, but still remains on the bottom leaves. The bottom leaves are starting to deteriorate in terms of condition, but I'm not sure if this is case of them dying off given over 50% yellowing.

Now, I've been doing some research on this, and BioBizz state that 30% of the nutrients are available instantly, and 70% are available between days 1 and 3 after watering, which could possibly be why I'm not seeing the issue stop just yet.

Additionally, now that the issue has progressed a little, I'm starting to lean toward a K deficiency due to the yellowing/rusting from outer edge in, burnt tips, and the veins remaining green.

There have been no signs of nute burn from the last feeding.

She's due another feed, so going to measure PPM going in, PPM coming out, as well as PH going in and PH coming out. I'm not sure how relevant PPM is though given that I'm not using synthetics.

 

[Frank56]

Update:

Fed her at half strength again (will give plain water next time), with 1.5L of water so I could collect a good amount of runoff.

PPM going in: 500
PPM coming out: 530

PH going in 6.5 (adjusted this time)
PH coming out 6.55

This really does make me think it's an underfeeding issue. Would be good to get more experienced thoughts

 

[Frank56]

24h later update:

Issue is still persisting, and it looks to be moving slowly up the plant; I wouldn't say it's moving up quickly. Some of the first leaves that I showed pictures of are now almost fully yellow, with some signs of rusting/necrosis. The plant itself, higher up, looks in really good health though... like almost perfect (lights off in 1 hour hence the drooping). Do you think I should up the feed from half strength?:

The first image here is the same leaf as the same as the second image in my last post with images, just so you can see the progression.

Really at a loss with this one guys, any help is hugely appreciated.

 

[Frank56]

One of the inner/smaller leaves had progressed a bit further and fell off naturally. Here's how it looked, which to me, looks pretty typical of a nitrogen def. Could stretching you see before full on flower be the cause for more N? She is definitely stretching a lot (I know this can be a sign of K def)

 

[Glassfarm]

Ssme thing happening to me right now..any luck with upfeed? I'm not sure if I'm blasting it with too much or not enough? I havent been feeding Bloom with grow and wonder if it needs more N? End of week 4 flower for me.. here a shot if her

 

[Frank56]

Ssme thing happening to me right now..any luck with upfeed? I'm not sure if I'm blasting it with too much or not enough? I havent been feeding Bloom with grow and wonder if it needs more N? End of week 4 flower for me.. here a shot if her

Hey man, the upped feeds did seem to slow it down considerably, and it's an at a point now where I'm not too worried. I've lost a few fan leaves to yellowing/necrosis but she's looking in really good shape right now overall compared to when I posted this.

If you're using BioBizz like me, you've got to use the grow and bloom together (the grow contains P and K too).

In short, I think this issue would have been a lot worse by now if the feeds were not upped. I'm currently feeding at full strength (Week 7), and the yellowing has practically stopped (if it's present, it's extremely slow at progressing).

Here's how she's looking today: