Top leaves yellowing, pH & light OK...

Sick Plants & Problems
#1

The short of it is that I used Green Cleaner, to successfully remove some Aphids that were found last week in very low numbers. I watered the plants with 7.3pH water Sunday, and I have these issues, which presented themselves to me as either a Zinc deficiency caused by pH, or light stress, which seemed impossible given where the plants were. The pH of the plants was checked out at 6.5 and 6.2, ruling out a pH caused Zinc deficiency. More detailed explanation and pics below.

I am in veg, growing in Pro-Mix which is mildly amended using DTE products, same veg mix I’ve been using for any new strain that comes into the garden until I figure out how much food it likes.

Unfortunately, I spotted some Aphids on a few plants one week ago. I culled 4 plants, and I did not see any others on the rest of my plants. I sprayed with Neem oilTuesday night, and two days later when I got some Green Cleaner I sprayed with that on Thursday and again Sunday. I saw a few bugs late last week, but nothing since. I used green cleaner at the recommended strength, but I was supposed to decrease the mixture strength for the second application, and I failed to do so lol

On Sunday the plants also received a watering. For many years I simply used my soil mix, and used tap water that was left in an uncapped bottle for at least two days. I recently started up a few DWC and using my pH meter I noticed the tap water was pH 8+ so I pH the water I used to water these plants on Sunday down to 7.3 ( I was hesitant to use much pH down in my soil, since I never had issues before, so i didn’t want to go any lower than that)

ph65
ph651512×2016 412 KB
ph62
ph621284×2778 337 KB
yuck3
yuck31284×2778 375 KB
yuck2
yuck21284×2778 357 KB
yuck1
yuck11284×2778 387 KB

4 Likes
#2

That pen is pretty neat. That would save a lot of time compared to a slurry test

I too run into this issue a lot where my plants go from a perfect green and then go light green out of nowhere. I hope you figure it out, im still trying to figure it out

2 Likes
#3

Had no clue they had a soil ph pen, that’s neat. I don’t know if that’s super accurate because in soil the microbes will help buffer the ph right at the root.

2 Likes
#4

For me it’s a lack of mag and or cold temps typically.

2 Likes
#5

I can see the cold temperature as being something that changed, as they were recently moved from the warmer veg room to the flowering area, which is cooler. However, I have been using that area for a long time. I’ll definitely keep this under consideration and do some research

3 Likes
#6

It’s just something I noticed in my environment, typically around seasonal changes.

2 Likes
#7

That would make sense in why i always run into this issue. I rarely push epsom salt or cal mag and my temps fluctuate from 69-70 lights off to 71-75f lights on

2 Likes
#8

yeah, I really like this thing lol. Hanna makes one too

3 Likes
#9

@jaws got me on the Epsom salt spray train. You can do 1/4 to 1/2 tsp per gal. It really helped the more finicky strains I have.

8 Likes
#10

Yea i need to implement that into my routine. I only use epsom salt or cal mag when i see issues like a dummy

2 Likes
#11

Did you use the neem oil just before lights out, sometimes I find it can burn the plants if they get a lot of light straight after application.

The cold will certainly slow down your soils bacteria conversion of nutrients to food, switching over to flowering can cause this as well as the plants change hormonaly and require different nutrients.

I would just wait and let them settle down into pre flower before adjusting anything a little litfa goes a long way

2 Likes
#12

Thanks, yeah, I’m gonna sit tight on any further action. Only thing I’m doing is giving them a good rain shower once the lights turn off of just water.

Good point about the lights after application. It wasn’t a long time before lights went out, but it definitely is another possibility, particularly on Sunday I did it in the afternoon and it may not have been a long enough time before I turned them back on.

Thanks! Sometimes if you think through things by yourself you can overthink and over complicate the matter

2 Likes
#13

I’ve always added either DTE Azomite or Green Galacial Rock Dust for minerals, but I may look into that as well.

1 Like
#14

Yeah panicking usually created more problems for me when I first started growing, caused more problems than it solved lol. Then I was given a great tip and got some super strength LITFA

4 Likes
#15

Heres a close up of the worst looking leaf. Cant find any bugs idk what is causing the holes lol

image_50385921
image_503859211896×4032 331 KB
image_50425089
image_504250892011×3024 253 KB

3 Likes
#16

Looks more like bugs than necrosis, the aphids you found wouldn’t cause that damage though.

2 Likes
#17

I think this problem is related to an over application of the Foliar sprays, Neem and then Green Cleaner. I do not have any reasons to suspect something is wrong in the growing medium nutrient or mineral wise. The pH is good, and they have been growing very well in these pots for some time prior to this, and I have been using basically the same soil mixture for a long time.

Who knows what all the chemicals combined and did, how soon exactly the came back on or how long it was off. I shoud have been a little less aggressive but I never had Aphids and my plants were perfect, probably overreacted some. Lesson learned. I’m going to continue with the nightly showers of straight water, and I’ll reevaluate and update this weekend. I appreciate y’all’s input. Thanks

5 Likes
#18

Now I am thinking about it again, I remember I once had very semetrical spaced and shaped holes in leaves that was caused by foliar spraying lots of different chemicals, when I was getting rid of mites, that really confused me, I was using alternating mixtures of alcohol, bleach, neem and sulphur, I think it was the sulphur that turned into sulphuric acid when combined with water under the lights over a couple of days sutting on the leaves.

#19

Hey, thanks. I was planning to post an update here this morning. The plants are on their way to making a recovery, some of them are already putting out some new growth that is 80-90% all the way healthy.

So the update I wanted to post was that I still believe the Neem application followed by two applications of green cleaner definitely caused some issue with the leaves that were there, and potentially effected some new growth, as well. However, the bugs appear to be completely gone. It should be noted that I did cull 4 plants, as the rest barely had any bugs when I first noticed them. I think that was important and if somebody stumbles on this thread I don’t want them to think neem and green cleaner wiped out an aphid infestation in 4 days with only 2 applications

In addition to the foilar spray causing the trouble, I inspected every other variable that I could over the last few days between a busy work schedule. I discovered that my <$20 yellow pH meter was GARBAGE. I believe this also attributed to the issue. My new pH pen did measure the soil pH to be good, but I believe @JustANobody is correct, that the microbes will create a small buffer at the root zone and the meter could be not totally accurate due to that naturally occurring buffer.

I watered twice with water which was pH using the old pen prior to receiving the new pen. Before that I just used the dropper pH tests or I didnt pH the water. When using the new pH pen I discovered that a reading on the bluelab pen of 7.0 registered at 7.9 on my cheap pen which I now disposed of. I believe this definitely caused an issue, so I flushed the 6 most effected plants and they have all responded very well since, as noted above.

I am getting rid of my cheap TDS meter as well and will continue to monitor everything. The TDS meter is for my DWC, as this is the first time doing that, I have 3 going there.

Thanks again for sharing your expertise, hope you all have a happy weekend with lots of new growth

2 Likes
#20

I went through a couple of cheap ph pens before I realized they were not worth the 25$ every 6 months to replace them, and got a really good one for $110 that has lasted me 5 years now and is really accurate and only needs to be recalibrated once a year and is usually only out a couple of 10ths of a point.

1 Like