yellowing from stressful training?

[kushtrees]

I decided to do some high stress training of my sfv og and since starting I have noticed much lighter green growth and even some slight yellowing.
I am pretty sure its not a defiency as I have ran the same strain with the same nutes many times before and never seen an issue, I even have some sfv that arent being trained using the same nutes and they look great.

Im currently using RO water w/ calmag and HG nute line in a 1:1 coco perlite mix under T5s fo veg

The only things I can possibly think of are: either they are getting topped, trained, and deleafed too much...
or, its a very mild Mg defiency from too much Ca. but I find this unlikely as everything else not being HST is looking good.

Can stress do this? if so will just backing off the amount of HST fix this little issue? thanks everyone!

 

[Snow Crash]

I decided to do some high stress training of my sfv og and since starting I have noticed much lighter green growth and even some slight yellowing.
I am pretty sure its not a defiency as I have ran the same strain with the same nutes many times before and never seen an issue, I even have some sfv that arent being trained using the same nutes and they look great.

Im currently using RO water w/ calmag and HG nute line in a 1:1 coco perlite mix under T5s fo veg

The only things I can possibly think of are: either they are getting topped, trained, and deleafed too much...
or, its a very mild Mg defiency from too much Ca. but I find this unlikely as everything else not being HST is looking good.

Can stress do this? if so will just backing off the amount of HST fix this little issue? thanks everyone!

This has a lot to do with where the yellowing is and how old these plants are.

Get yourself a bunch of runoff and test the EC if you can. If the runoff EC is overly high then just keep running your nutrients through it. If the runoff is pretty close to what you are using then we can assume this is a natural deficiency.

During the 5th week or so of use I notice that the coco fulfills its calcium buffer and adding continually high levels of it is too much. I think you can cut the Cal-Mag Plus back to 2ml per gallon (which is a 0.2ec increase, or ~100ppm). The HG line is what you want to start pushing more of if you need to increase anything. The extra Nitrogen, Phosphorus and Potassium will help.

If the yellowing is in the "meat" of the leaves while the edges and veins remain mostly green then you're looking at a cation imbalance (common in coco that has a salinity issue). Ensure you get a little extra runoff for a bit, and maybe add a pinch of epsom salt in a large reservoir (like 1/4 to 1/2 tsp per 5 gallons). That extra little bit should be all it takes to balance things out.

Veg in coco is usually pretty basic. Sometimes I notice yellowing when I let the media get a little too dry. This usually starts on the bottom most leaves. The ends crinkle up a little, almost like mold, while the leaves just slowly bleach out. This is actually a phosphorus deficiency, but it's caused by the media getting dry and salts precipitating.

So... If it's slight yellow in the middle of the plant then more food, less cal-mag plus. If it's yellowing closer to where the lights are then lower your temperatures and increase the magnesium with a little epsom salt. If it's near the bottom of the plant and bleaching out then add more phosphorus.

The general description of "my plant is yellowing" without any description to the age of the plants, the environmental conditions, the nutrient strengths, the runoff EC, any pH information, a picture, or even a reasonable description of the issue... You're not going to get a tidy answer unless you can ask a tidy question.

 

[kushtrees]

thnx for the reply SC, but thats not really what im trying to figure out.
I know its not a nute issue these plants were transplanted 3 weeks ago from the cloner getting flushed weekly and with the exact same nutes Ive always given this strain and the ones not getting trained and topped as much or at all are fine...

I shoulda been more clear youre right. I want to know if high stress training can cause yellowing, thats all, sorry for the mix up

 

[Snow Crash]

Yellowing is always a nutritional thing.

By "high stress training" are you talking about topping/Fimming, defoliation, or super cropping? All could be interpreted under the HST umbrella. Much in the same way Bending and Scrog fall under the LST umbrella.

I think if the plant is dedicating enough energy to generating new shoots you could experience an iron deficiency. Here's a link to iron deficiency in plants:

The Cal-Mag Plus should be providing all the iron you need, and contrasting to my earlier advice, you may need more of the stuff (up to 8ml/gallon) to get the chelated iron these trained plants require. Check the link to see if that matches up.

The new tops and the iron thing during a moment of intense growth (as you get more leaves you get more energy to make more leaves and the process becomes exponential). Maybe it is a combination of the high cation media - fully charged with calcium interrupting the uptake of a much less abundant but necessary element Iron - and the number of new tops you have all pushing a lot of new growth.

Does that make sense?

 

[kushtrees]

That does make SC thanks, and yes HST im topping and deleafing prolly a lttle much for how young they are. Also run off is at 1.1 and im feeding at 1.2 EC so im probably going to up the base nutes

Im actually at 12ml calmag as I was seeing Ca defiency on my OGs and thats what they seem to like. Im def thinking its too much Ca making Fe or Mg less available. Heres some pics its really hard to see though; its just very mild yellowing on the edges. Some leaves were slightly curling upward which is why I first thought Mg but now its looking more like a mild Fe or even another mild Ca def.

Hope the pics help, its not really easy to see but on the last one a little, and thanks for the input. I wouldnt have thought HST would require dif nutes but in retrospec it makes sense... thanks for the help again still trying to figure this out

 

[Snow Crash]

I do have some concern regarding your nutrient levels.

You say you are using 12ml of Cal-Mag plus

But you also say you are using a 1.2ec

12ml of Cal-Mag plus IS 1.2ec without having to add any more nutrients.

You might need to check the calibration on your meter. Every 1ml of Cal-Mag Plus is formulated to result in a 0.1ec increase, so if you're adding more than just Cal-Mag Plus then you need to look into calibration.

To me it looks like your plants suffered a momentary lack of Magnesium but have since recovered. If it seems like the problem is getting progressively worse then you probably want to cut back on the Cal-Mag Plus and start incorporating the Epsom Salt.

A foliar feeding of a little Epsom Salt will go a long way to resolve Magnesium and Sulfur deficiency. If your plants were in my garden I'd give them this foliar feeding once and see if they respond by stopping any interveinal chlorisis that is going on.

If the Epsom Salt foliar doesn't resolve the issue then I'd probably address the heat and the potassium.

Either way though, I think 12ml/gallon of Cal-Mag Plus is waaaayyyy too much. The HG line should have more Calcium per ml anyway. I'd cut back on the Cal-Mag plus to at least 6ml, increase the use of the HG nutrients, and start adding in like 25ppm of Epsom Salt with every feeding. Every grower has different methods, and if there is any single truth about cannabis it is that it grows well under a vast variety of conditions and nutrient ratios.

Something about the ratios in the media is out of tune with the state of your plant, possibly from the training. From the look of things it seems like it might be a cation imbalance and I think the most likely culprit to interrupt the uptake of iron, magnesium, or potassium is going to be Calcium. That's my take on it.

 

[kushtrees]

10 ml calmag is .6 for me on my truncheon so cant really calibrate it and I just cleaned it. It is more than I thought as last time I checked it was .4 so thats my bad on the cleaning it looks like.

Im def ganna bring the calmag down to 5-6 and up the bases a little, as after cheking Im pretty sure its too much Ca locking out Mg that makes the most sense. thanks for the advice SC I shoulda checked my meter earlier haha

I would love to add epsom actually Ive been looking into using that and a Ca suppliment instead of Calmag plus as Im not a fan of the extra N.

Do you know the dose of epsom for 25 ppms of Mg. I havent used that stuff in like a year so I dont remember the amounts. thanks for all the help SC hopefully this works out well

 

[desertsquirrel]

Seems to be a bit of conjecture going on here so i figured some math might help...

First of all many things can cause yellowing of leaves, not simply nutritional issues. Heat, over watering, underwatering, Co2 excess, pH imbalance, toxic off gassing, and yes, stress, can cause yellowing of leaves.

My first question would be how much defoliation are you performing? International Arbor Society recommends never removing more then 20-25% of any plants foliage. Also what goal are you trying to achieve by using multiple stressful cultural controls on your plants?

That being said im not going to try and give you a nutrient analysis w/o much more info of (including pic) your plants. However seeing what you are working with might be helpful to you....

Here is H&G at 10 mls (Actual available ppm):

H&G
(3-12-6) (NH4) 0.7% (NO3) 2.3% Mg0.5% Ca2% Fe0.1% S0.09% Mn0.05% @10ml/Gal

N 140

P 50

K 250

Mg 20

Ca UNKNOWN

S 0


Now, with no real numbers on H&G's Ca its hard to know how much is to much, or how much is enough for that matter. It can however be noted that Calcium nitrate is the leading ingredient in Part A, so we cannot take (unknown) to mean 0 thats for sure.

Here is cal-mag at 12 ml/gal (Actual available ppm):

Botanicare Cal Mag Plus (2-0-0) Mg1.2% Ca3.2% Fe.1% 1.0208 g/mL @12mL/Gal
N 65
P0
K0
Mg 39
Ca 93
Fe 3.2
Derived from: Calcium Nitrate, Magnesium Nitrate, Iron EDTA

As you can see the actual available ppms for cal-mag are much much lower then are read on your meter (another huge benefit to profile use).


With Unknown Ca, its very hard to tell if 12 ml is too much to use with H&G. We can however look at the N and the Mg and use those as a guide. Here is where the problems arise because H & G is notoriously high in N and notoriously low in Mg.

In general profile ranges i like and work with look something like this:

N: 100-150
P:40-60
K:180-250
Ca: 80-120
mg: 40-80
S : 40-80

The profile is whats important, not how many mils come out of what bottles.

Hope that helps.

Oh and the Epsom profile you asked for:

Epsom salt, magnesium sulfate, Mgso4:

Mg: 9.8%
S: 13%

or

1g Epsom salt =

Mg: 98 mg or 98 ppm/liter
S: 130 mg or 130 ppm/liter

or

1g/10 liters =

Mg: 9.8 ppm
S: 13 ppm

or

1g/gal=

Mg: 26 ppm
S: 34 ppm