Help me please: 4 weeks, nutrient burn or lack of K?

[Meo]

What nutrients are you using. And I think you wanna be around like 500-800 ppm....

These are the basic A and B mix plus some microminerals and some Vitalizer. I have decided to wait 8 hours and if they’re still turning yellow I will try 500ppm.

 

[Meo]

It’s broken. I think. No way your tap water is 25ppm. What are you using nutrient wise?

Haha I tried salt and pepper water and it was looked just fine~ forgot to say for the 220ppm just now, I mixed 45 ml of each A and B mix for 35L water. This is 1/4 of normal usage of plants. And they’re only 4 weeks old still babies I didn’t want to give them too much lol

 

[Curbcalamity]

yeahbn man 350 ppm is way to low. you using a bluelabs truncheon? aim for like around 800 ppm. you might be able to go a touch higher but in DWC they need a bit less nutrients than normal.
bottled water has way more than 3ppm. mnore like 200-300. my tap water is like 400 ppm out the tap.
try half recommended dose of the nutrients. cos 4 weeks is old enough to give them a good dose. don't need to baby them to much anymore. also H2O2 while keeping the reservoir free of nasties, it actually doesn't produce atmospheric oxygen it forms a slightly different kind that a plant wont absorb anyway and actually causes much faster oxidization of nutrients like iron into non water soluble forms.

 

[Meo]

yeahbn man 350 ppm is way to low. you using a bluelabs truncheon? aim for like around 800 ppm. you might be able to go a touch higher but in DWC they need a bit less nutrients than normal.
bottled water has way more than 3ppm. mnore like 200-300. my tap water is like 400 ppm out the tap.
try half recommended dose of the nutrients. cos 4 weeks is old enough to give them a good dose. don't need to baby them to much anymore. also H2O2 while keeping the reservoir free of nasties, it actually doesn't produce atmospheric oxygen it forms a slightly different kind that a plant wont absorb anyway and actually causes much faster oxidization of nutrients like iron into non water soluble forms.

Ťhis is the meter I’m using, and the 3ppm is bottled PURE water. I have not used H2O2 yet.
Everyone is saying they’re starving. I will feed them now~
460ppm 5.8ph

 

[Meo]

hp: 5.8
ppm:460

They continue to turn yellow and burnt at the tips :’(

 

[013]

Hey Meo,

Welcome aboard! I think homemade nutes and work arounds are cool but you’ve got to dial it in - anyway it begs the question...... what are you doing for calcium? I saw where you mentioned the N and the mg but have you got a calcium input?

 

[farside05]

These are the basic A and B mix plus some microminerals and some Vitalizer. I have decided to wait 8 hours and if they’re still turning yellow I will try 500ppm.

There's something up with the Part A label. It says 114% for water-based phosphoric anhydride. That's impossible. I bet it's supposed to be 11.4% given the other numbers. Anyway, it looks like these are powders. If so, add 2.5g per gallon (3.79 liters) of both Part A and Part B. That will give you about 130ppm from Nitrogen and a total ppm of about 650. When the plant is fully grown, up it to 3g of both Part A and Part B. That gets you to 158ppm from N, which is a happy spot for most cannabis plants. Feeding by ppm alone is pointless. You must know what that ppm consists of. The numbers actually play out quite well for generic nutes and would be comparable to Mega Crop's or Jack's 2 part powders (except quite a bit more Sulfur).

A&B Mix.jpg

• farside05
• Apr 14, 2021

 

[Meo]

Hey Meo,

Welcome aboard! I think homemade nutes and work arounds are cool but you’ve got to dial it in - anyway it begs the question...... what are you doing for calcium? I saw where you mentioned the N and the mg but have you got a calcium input?

Hi 013~ there is 19.5% of calcium in my B mix.

 

[Meo]

Thanks for the details! And yes it’s 11.4% not 114%, it got screwed up after i used the translator camera thingy.
I kept an eye on what’s in the nutrients and what the girls need. As of now I’m feeding
Water: 35L
A:110ml
B:150ml
Other micromineral: 3ml
I did a bit of calculation and it’s around 5.4g of N in 35L water.

So i tried both lowering and then upping the ppm, but the same problem still occurs. Or should I wait a bit more to see what happens?

 

[bruno12345]

Well, the part you have cut off from the leaf, the margins of the cut will die or be spotted like it is.

I would maintain it near 600ppm like the friend said above.
After 2, to 3 days, you should have vigor coming back, and slowly better leaf coloration.

Once i cutted the tip of my nut burned plants, and the place i cutted made a discoloration. Thats why i never cut leaves parts anymore.

i would watch the new growth and plant development. Youll see in one or two days if youre in the right spot.

____________________
Edit:
Maybe some hydroponics expert can tell if you arent overdosing in calcium, which would cause deficiencies in Mg and K.
K deficiency may appear as burnt leaflets margins.

"Excessive calcium uptake by a plant may lead to disturbances in ion balance, to the disadvantage of other nutrients (such as potassium and magnesium), or to changes in cytosol pH and a decrease in solubility of some ions, e.g. of iron (Chaanin and Preil 1992; Balakrishnan et al. 2000)."

 

[Enjoil]

hp: 5.8
ppm:460

They continue to turn yellow and burnt at the tips :’(

480 is still looooowwww! Change nutrients, or start growing in soil. I don’t mean to be blunt but... lol

 

[Meo]

Well, the part you have cut off from the leaf, the margins of the cut will die or be spotted like it is.

I would maintain it near 600ppm like the friend said above.
After 2, to 3 days, you should have vigor coming back, and slowly better leaf coloration.

Once i cutted the tip of my nut burned plants, and the place i cutted made a discoloration. Thats why i never cut leaves parts anymore.

i would watch the new growth and plant development. Youll see in one or two days if youre in the right spot.

Okay thanks! That’s exactly what I’m going to do. There’s always so much to learn the first time lol!

 

[013]

Cool, shit - my bad I read right past that

 

[Meo]

now
hp：5.8
ppm：610

There’s always so much to learn the first time~~~lol

 

[Meo]

Well, the part you have cut off from the leaf, the margins of the cut will die or be spotted like it is.

I would maintain it near 600ppm like the friend said above.
After 2, to 3 days, you should have vigor coming back, and slowly better leaf coloration.

Once i cutted the tip of my nut burned plants, and the place i cutted made a discoloration. Thats why i never cut leaves parts anymore.

i would watch the new growth and plant development. Youll see in one or two days if youre in the right spot.

____________________
Edit:
Maybe some hydroponics expert can tell if you arent overdosing in calcium, which would cause deficiencies in Mg and K.
K deficiency may appear as burnt leaflets margins.

"Excessive calcium uptake by a plant may lead to disturbances in ion balance, to the disadvantage of other nutrients (such as potassium and magnesium), or to changes in cytosol pH and a decrease in solubility of some ions, e.g. of iron (Chaanin and Preil 1992; Balakrishnan et al. 2000)."

Got it! I will observe for a couple more days and do some more research on calcium. Thank you so much for the super detailed feedback!

 

[Sativa1970]

The problem with using PPM is that it isn't a universal scale. There are 3 different scales so the feed chart (or advice) you are using has to match the PPM scale of your meter. This is why so many people are dead set on using EC, it is universal. I have a PPM meter that shows I feed at 700-800 PPM. My tap water is 210 PPM. Carbon micro filtered water in the grow room is 140 PPM and bottled pure distilled water is 40PPM. So the meter works but the scaled calibration is misleading. If you only have a PPM meter mix by volume as directed then test PPM to get a base number. That number will be a little heavy on the food normally.

You are using distilled water and NPK but are you adding the micronutrients and silicates?

 

[GoogleGenie]

Apologies, I'm a little late to the party. My 5c, and to reiterate the advice you've already received...

They're hungry. But this isn't a big problem. Far easier to correct than over feeding. It's difficult to advise you on the PPM level you want. If you are running a hyper aerated temperature controller res, you want your ppm a little lower - I do, and aim for 250-350ppm at this stage. Roots take up nutrient far more efficiently when the reservoir is kept at the ideal temperature (18c-21c) and you are blasting the water with oxygen at all times. If you are not using a chiller, and/or aren't using a powerful pump you can increase you nutrient strength. But even then, personally, I wouldn't exceed 450-500ppm. There are many factors that determine your ideal nutrient strength, environments first and foremost, but then of course the plant itself.

The only time i'd be looking to bump it up is when you commence flowering, and then again a little around half way through.

If you start to see yellowing/browning/crisping/twisting of the lower leaves, this could be an indication that you have a root problem. I'd recommend adapting one of two practises when growing DWC
- Sterile - Using H202 (No point in using beneficials, H202 will kill them)
- Beneficials - Using beneficials (you cannot use H202 here)

Roots are always my first priority, in particular when growing in DWC. Happy roots, Happy plant, Happy yield.

That being said, if you are unable to regulate the temperature of your res (you do not have a chiller), I would highly recommend something like Hydroguard or z7 is an alternative i believe. It's expensive, but will help keep your roots nice and healthy. I never like advising people to spend money, but I make an exception with Great White and Hydroguard.

 

[JD Green]

The problem with using PPM is that it isn't a universal scale. There are 3 different scales so the feed chart (or advice) you are using has to match the PPM scale of your meter. This is why so many people are dead set on using EC, it is universal. I have a PPM meter that shows I feed at 700-800 PPM. My tap water is 210 PPM. Carbon micro filtered water in the grow room is 140 PPM and bottled pure distilled water is 40PPM. So the meter works but the scaled calibration is misleading. If you only have a PPM meter mix by volume as directed then test PPM to get a base number. That number will be a little heavy on the food normally.

You are using distilled water and NPK but are you adding the micronutrients and silicates?

If distilled water is giving a ppm reading other than 0, your meter is out because distilled H2O has no particles in it, thats why I only use distilled.

 

[Sativa1970]

If distilled water is giving a ppm reading other than 0, your meter is out because distilled H2O has no particles in it, thats why I only use distilled.

That was my point. Distilled water has an acceptable margin of error by EPA standards to still qualify. Distilled can be 5 PPM and keep the label claim. My other meters showed the distilled at 3 PPM but that one meter shows 40PPM because of the scale.
I only use distilled water to test my meters when I think they may be off or I get a new one. I am fortunate to have good micronutrient levels in my tap water other than the cloriens and florides. My filter and aerator drops those down to less than 1 PPM according to the lab results.

 

[Meo]

The problem with using PPM is that it isn't a universal scale. There are 3 different scales so the feed chart (or advice) you are using has to match the PPM scale of your meter. This is why so many people are dead set on using EC, it is universal. I have a PPM meter that shows I feed at 700-800 PPM. My tap water is 210 PPM. Carbon micro filtered water in the grow room is 140 PPM and bottled pure distilled water is 40PPM. So the meter works but the scaled calibration is misleading. If you only have a PPM meter mix by volume as directed then test PPM to get a base number. That number will be a little heavy on the food normally.

You are using distilled water and NPK but are you adding the micronutrients and silicates?

I see! I have EC on my ppm meter as well, i will post both ppm AND EC next time. Thanks!!