Bronze spots and fan leaf dying

[Myskellos]

HI everyone, I did make a post yesterday, maybe in the wrong section about my fat Banana.

https://www.autoflower.org/threads/whatss-wrong-with-her.81899

I see that those rusty spots continues and I can see them also on a higher set of leaf, not just the lower one. The tips are still discolored, the new ones are clawed. What is going on? I have no ph/ec pen, but I followed the biobizz schedule up to week 3 (the first with bloom) for light mix.

Any tip?

 

[Arthur]

Copy and paste, then fill this out. We need more info about your setup first.

-Problem: (brief description)
-Medium/grow method: soil; soilless-- coco, or peat based like Promix, etc. (please provide the actual product name); DWC, NFT, etc.
-Feed and supplements used: include brand, dosage/strength, frequency of feeding and watering (alone); method-- by hand, drippers, rercirc' or drain-to-waste,... N-P-K #'s too if you can!
-Water source: RO/DI; tap- dechlorinated-?..... EC or TDS reading; pH (don't bother with this on RO/DI, do bother with TDS/EC though to confirm it's working well enough)
-Strain and age
-Climate: night and day ambient T and RH%; res' temperatures; any extremes in T/RH% exposure
- Light used: HID, LED, COB, combo of,... wattage; light cycle hours (20/4, 18/6 , etc.); distance to tops....
-Additional info: How long have the plants been affected?...How fast did symptoms appear?... Anything else you think might be relevant..

--Pictures including WHOLE PLANT PICS, and troubled leaves.. use normal light or flash as other light sources ruin color rendering, critical for diagnostics!

 

[Myskellos]

-Problem: Plant is 23 days old. From week 2 the plant has got bronze spot on fan leaves. One or two eventually died, now there are two other more interested by those brown spots, and they're getting bigger. Also, I saw those spot on a higher leaf. Moreover some of the top leaf tips seems discolored, maybe too much light?
-Medium/grow method: soil, biobizz light mix
-Feed and supplements used: biobizz grow, top max and bloom as follow:
Week 2 = 0.4 ml/l BioGrow
Weel 3 = 1 ml/l BioGrow
Week 4 (yesterday) = 1 ml/l Biogrow, 0.5 ml/l Bloom and 0.5 ml/l TopMax

-Water source: tap water, company analysis says ph is 7.5. I don't have a pen to measure
-Strain and age: RQS Fat bana auto, 23 days
-Climate: T is swinging between 23 to 15°C, RH between 60 and 40%
- Light used: MarsHydro Led TS1000, 150W nominal power, used at 100% at 50 cm from canopy (now moved a bit, 55-60 cm).

 

[Myskellos]

Here are some pics without the led running, just the flash

 

[DCLXVI]

I see two things that I struggled with as a new grower, better more experienced people can probably point out other issues but:

1) Bring the temp up. 15c is too low and 23c is where your low end should be. 27/28c on the high side.
2) pH needs to come down a bit. Buy a decent pH pen. They are like $20 off amazon.

Also budget for some calibration fluid and storage solution
(approx amazon $$)
I bought the Milwaukee ph600AQ $23
General Hydroponics 7.0 calibration fluid $12 (aka standard reference solution)
apera 3m kcl storage solution $14

Buy whatever calibration and storage fluid you like. These are just what I used.

$50 or so. I can't speak for the $10 cheap vivosun/china testers but they might work fine if they have a calibration function. They also might drift a ton and need calibration more often. Mine certainly had a break in period and I calibrated once a week until it stopped drifting.

 

[Myskellos]

Unfortunately the grow tend is in a pretty cold room, about 18c during the night and lately is very cold outside. Moreover the tend is exposed on the external wall, I'm trying to move it next to the internal wall so I might raise the minimum temp a a few degrees.

It might be that when is really cold, about 15c, the plant does not absorb as much phosphorus at it should, so this can be a possible cause of what I'm seeing.

I will get a ph/tds pen as soon as possible. But I have a doubt: I read somewhere that when using organic nutes such the biobizz line is not really useful to have a tds reading, since they does not provide a measurable quantity of nutes, they are not ready to be absorbed by the plant, instead they need to be worked by microbes in soil. So using the tds pen won't tell me much about a possible nutrient lockout. This is how I understood the matter, but I'm not sure about that. However thanks for the precious tip!

 

[Myskellos]

Hi everyone, I did get a ph and tds pen meters. Little update before digging into the data: the fat banana is growing, the yellow tips are still there, mostly on the top and new leaves. I raised the light, a marshydro ts1000, a little, now they are 60 cm from canopy.

The following issue are affecting the Fat Banana (27 days old):
- yellow tips
- some brown spots on older leaves
- some yellowing between veins
- some red colouration of stem where the leaf begin

Now as I said, I got a ph/tds pen from Amazon, dustgo brand. After calibration here is what I found:

- tap water: PH 6.8, TDS 344 ppm / 694 uS/cm
- filtered tap water (with carbon filter inside): PH 7.4, TDS: 336 ppm / 674 uS/cm

Yesterday I added the following nutes to the plant: Biobizz BioGrow 1 ml/l, BioBloom 0.8 ml/l, TopMax 1 ml/.

I tested the same nute concentration with the pen:

- Nutes with tap water: PH is 6.7-6.5, TDS is 630 ppm
- Nutes with filtered tap water: PH is 6.9, TDS is 640 ppm

Up to now I always gave plant the plain tap water. So the TDS is looks okto me, even if being the Biobizz nutes organic, does these value even make sense? I read somewhere that water with nutrient should fall into the 400ppm – 800ppm range.

I saw this workshop of Biobizz about using their product (in spanish, but the youtube translation is pretty good). From minute 13 to minute 32 he shows a fertigation example.
It says that their nutes are designed to work with water of EC 0.4 (i think is in mS/cm. Still, is not really clear to me which is the conversion factor that is using between EC and TDS, mine I think is 0.5). Then he adjusts the ph of the nute solution to ph 6-6.2.

Soooo... wrap up... should I be worried? Is some nute burn / lockout going on? I have no idea of what to do

Edit: some additional input: when I water/fertigate I never do that untill runoff. I do it until the soil looks wet but not soaked. For reference, I use fabric pot. Should I always water/fertigate until I get some runoff? Also, Biobizz advice is to use nutes to every watering to avoid ph fluctuation, but I read that just a few days ago. So, up to that i used to give nute / water / water / nute ....

 

[Myskellos]

HI everyone, I contacted biobizz about those issue with the Fat Banana. Big up for those guys for the prompt response, and also to @Master_gRoshi that took a look and replied me in chat.

For reference to anyone using biobizz nutes I paste here the mail, there are some interesting take away:

From what we can see, it looks like your plant would benefit from a bit more phosphorus…

When growing auto strains with Biobizz, we actually recommend to plant them in Light·Mix and use our Nutrient Schedule for All·Mix. In this way, we give lower doses of nitrogen, but maintain the P and K input with full dose of Bio·Bloom.

Keeping the full dose of Top·Max is also very important, as this flowering stimulator helps the plant absorb the nutrients you give in each watering and transport them to all the parts of the plant.

Also, as you mentioned, we recommend to use the Biobizz products in every watering. As you have skipped feedings, the plants may be a bit underfed.

We also recommend to adjust the pH of the nutrient mix (Biobizz products + water) to the optimal range of 6.2-6.5 right before watering.

If you want to help your plants recover sooner, you can always add a bit of Alg·A·Mic to the nutrition plan and help them get back to their green and lush state.

With these adjustments and a bit of patience, your plants should recover and become

healthy and productive again J

 

[Myskellos]

Hi, I'm continuing the thread hoping that someone can help me since the plant is not doing any better. I have the feeling that things are spiralling out of control.

So, after the Biobizz mail I followed the All-mix schedule as suggested. I fed the plants with BioGrow 1 ml/l, BioBloom 2 ml/l, TopMax 1 ml/l, and fed it every watering up to 1st of Feb. I always corrected the nute solution with lemon juice to 6.2 - 6.5. The plant is streching and the growth doesn't seem do be slowed by any mean, since in a week has grown 10 cm.
Yesterday I gave it the same nute but with a BioBloom of 3 ml/l, since I thought that the P deficiency is not corrected.
I say this because of the lower leaves still getting brown splotches and becoming crispy and papery. Also the red stem seems to be a common indicator of P deficiency, moreover as I understood the organic nutrients take some time to be available. So, that's why I bumped up the bloom nute.

Before the last feeding I did a slurry test by taking a spoon of soil at 5-7 cm depth and added 2 parts of distilled water, stirred for 10 minutes and let the slurry in a glass for 30 minutes. I expected to have the pH fucked up, and instead it was 6.5.
After the feeding I collected the runoff and it was 6.4. So, I guess the soil is ok and there are no indication for nute lockout (for what those tests are worth...)
Temperature are fine, 23°C with lights on and 16/17 °C with lights off. As much as I know the P deficiency could be triggered by low temperatures, but it doesn't seems the case.

Phosporus (maybe?) deficiency aside, now what worry me the most is some brown dots appearing here and there, not only on lower leaves but also on upper leaves, in the nearby of flowers. Could it be some calcium deficiency or a progression of P def to upper leaves?

The yellow tips I'm pretty sure are due to a slight light burn. Overall the plant seems to carry on, but I don't think it will go far away in these condition. What can I do to get to the harvest with a decent yield?

 

[Bill.de.Cat]

Far from unsalvageable. Keep soldiering on.
Light stress is a good guess on the new growth yellowing. I'd defoliate the worst of the older lower leaves, raise lights, wait....wait....wait.... I know, patience is the hardest part of growing. Main thing is take little steps suss ing out a problem. Too much "fixing it" at one time can lead to introducing more problems than you had and you end up chasing your tail.