HELP! Leaf issue close to harvest

[YYCannabis]

This girl is an auto and 16 wks old. Harvest should be within a couple of weeks. What is happening?

- Upper leaves affected
- red stems similar to phosphorous deficiency
- DWC
- pH maintained to approx 6.1 - 6.2
- fed just Blend and bloom nutes.
- ***new light*** that I’m trying to find the right height above canopy. Lights are currently a few inches above the top cola.

Is this a nute issue or light burn?

Cheers
YYC

[duckman]

if it's restricted to only the upper leaves my guess is light burn...

[YYCannabis]

Just might be. I moved the light up another few inches as a precaution.
But still not writing-off nute issue. So close to the end that I don’t want to blow a tire on the last lap. 😁🤣

[duckman]

YYCannabis any chance they might have gotten a light burn from water droplets or similar on the leaves?

[YYCannabis]

No chance of that. But I’m curious about why you ask.

[duckman]

just wondering, I guess, about the pattern of the mottling on some of the leaves...but if there's only a couple of weeks left I'd say just ride it out...

[YYCannabis]

Having a closure look at the GWE plant doctor it looks like a calcium issue. I did a water change with fresh bloom nutes and added CalMag. I’m not sure if that was the right thing to do this close to the finish.

[Tersky]

I doubt it will hurt it. Calcium is not needed as much in flower as its used for cell wall creation in leaves and stems mainly so when i see those in late flower i tend to ignore it. That said, i grow in coco and use RO water so i always use a cal-mag supplement.

[YYCannabis]

Just an update on her. Still getting spots on some leaves that are higher up. I think the addition of CalMag has helped a bit. I also dialed back her nutes to half they were before.



Her sister is also showing signs. Her changes were much more sudden.



She’s still a few weeks away from harvest

Cheers
YYC

[Farmall]

YYCannabis .... sorry to add another opinion but like a-holes, we all have one so: the leaves look like a deficiency...if we are thinking lock-out causing deficiency, that lockout can also develop via excessive feeding. chemical fertilizers are salt based and your hydro nutrients maybe loaded? So if it’s not pH fluctuations preventing the uptake of nutrients, it could be excess nutrients causing lock by those salts building up. Thinking a complete pH balanced fresh water change could be a solution.After a few days, you could see that improvement

[Farmall]

By the way, kept my lights about 18-22” over the canopy but I had two that were poking through the arms and only the leaf touching the diode got crispy. Did not have any really “Light” specific problems. I I really thought I would. I believe the red stalks and stems are something like a sun tan. Maybe a protective process by the plant

[YYCannabis]

Farmall girls have been very thirsty lately since adding new lights...which meant more heat which meant more fans. I’ve been adding fresh tap water mid-week (pH adjusted) to the pails then full nute change on weekends. Maybe I’ll cut her nutes back like I did for her sister, and just more pH adjusted water this weekend.

[Farmall]

If you re up for it, try just plain pH’ed water. I hope that gives you a better solution. YES, these lights create activity within the plant and the do suck up 30-50% more water, which is a double edged sword if your salts are building up in the cell structures, plain water will dilute it down. When I’m in super soil, nothing but water...I get leaves a week or two before their ripe that look like something most gardeners would replace. Deep investigation still seems to point to ph and water practices, too frequent and to high 6.8, the well is 8.4

[Farmall]

What were and what are your temperatures... I get days when I open the zipper doors and see 76-78 after a 3-5 hour on time and early int the morning 67

[YYCannabis]

Here’s a log for today. The low temp timeframe to the left is lights out period. The massive drop in humidity is when I opened my tent to check on things.

[Farmall]

Your high temp is a touch over 80 (in my world) so I don’t think your heat is a problem and the humidity seems good although the consensus I read is closer to 50% this alone isn’t causing your leaf problem. I’m hoping the plain water bath will help to re-energize the leaves, clean out any lock and get the plant back on track. They surely have come a long way and will produce nicely. If you notice the fresh water improves the condition, replace that water with fresh water again but start adding low level nutes.... remember, they call it my 2 cents because that may be all it’s worth.

[oldjarhead100]

Farmall pretty much has this but like he said I have my 2 cents ,I have seen spots like that from my cheep leds to close, also from nute lock out have you flushed them real good .water to runoff and check run off ph and ppm , in coco I will use twice as much flush solution untill I see things change then I reduce it to normal levels on my last flush I recharge the coco with a double feed of cal mag, ok I just went back and saw your dwc ,in the first picture in post it looks like heat and light burn

[YYCannabis]

Thanks for the flushing advice. I’ll do that this evening. Since I’m running a DWC setup, is 24 hrs ok or too long for the root flush?

[Tersky]

In DWC there should be no reason to flush until harvest. There is no medium to flush. The only way nutes get locked out is because of ph issues or root issues. The water is the medium, so if you are doing consistent res changes there should be no reason to flush.

[Farmall]

Watch the leaf very closely. You won’t want to starve the plants of food especially now that they’re are starting to fatten up the buds. I actually think 24 hours may be enough under these new lights to get some throughput where the plants are drinking and exchanging compounds with the fresh water. I just don’t know but it is a conventional flush and in hydro usually lasts 3 days or so. Point is, you’re not flushing for harvest, you’re trying to vacate nutrient buildup.

[Farmall]

I’m thinking out loud here BUT, if you have a tds meter, I am wondering if your reading of your fresh water is ‘x’ and after 24 hours would that number be higher based on an exchange between the plant and it’s concentration of salts to the fresh water....sound logical but I don’t know if is likely...???

[YYCannabis]

I could just do it for overnight. Let it have both a light and dark cycle then check in the morning.

[YYCannabis]

Or I could just let it go it’s course. The spots seem to have stopped on one of them. Haven’t looked at the Jenny-come-lately sister to see if her spots are holding or growing.

[Farmall]

Great start for sure...if there is a change for the better, you’re in a greater position than leaving it to somehow flounder on it’s own since you’re trying to maintain bud quality. Nice to hear the it is receding on another plant

[FarmerJoe]

I would defoliate most of those leaves so the Buds can breathe better, Get a sense of Fall & focus all her Energy to the Buds. I’ve seen similar problems in the past and found that Adding or changing nutrients just make it worse. Overthinking it. she's ready to produce her fruit.Water and Air. Just my opinion but if it was mine that's what I do.

[YYCannabis]

Interesting. If it might help accelerate the buds that could be a good thing. The hairs on these girls are still mostly white with only a small % turning brown.
Since I have two identical plants doing the same thing, I’m going to try the defoliation on one and a root flush on the other then see what happens.

When you do your defoliation, do you remove all fan leaves or keep some of them? Seems like there is a lot of conflicting ideas regarding defoliation.

[Farmall]

YYCannabis those remaining leaves are the solar panels collecting light for food so I may not pick too many. The ‘conundrum’ is too little does little and too much, well...you get the idea