Rust Spot help: pics

[TripleCchronic]

Iv been having an issue with little red brown spots appearing on older leaves starting from the tips and working their way inward. Im in DWC using GHE flora trio. 10ml/g Micro 10ml/g Gro and 2.5ml/g Bloom + 9ml/g CAL MEND, 6ml/g B-52 and recently started 2ml/g UC Roots. Day temp 27 C Night temp 20 C, res temp 24 C, pH 5.7 - 6.2. Unfortunately my ppm meter is broken atm so no ppm info. Im wondering if my previous cal mag deficiency is now an excess issue. I had my fan break down for about a week so I only had my exhaust inline fan running during that time. Tried cutting out cal mend on last res change 3 days ago but am still seeing new spots. Im also seeing no evidence of bugs. Some of the leaves also seem deformed with holes in them but im wondering if that's just from rough handling.

 

[Glookies1]

I’m having a similar condition. Generally “rust” is a cal mag deficiency, but I’ve been feeding cal mag.

 

[iNeedMeds]

What percentage of calcium is in the CAL MEND? I see it has 2%N, so I'm guessing it's about 4-5% calcium
For one, you have a sulphur deficiency. That lime green colour is because you only have 7 ppm of sulphur, and typically most nutrient mixes have about 40 ppm in a full strength mix.

Another problem is that your calcium levels are very high. Your potassium levels are high, but your calcium is about double of what it should be in ratio with potassium and magnesium. As a result, potassium uptake is being reduced to the point of deficiency. The little white dots are from the potassium deficiency.

If you're in Veg right now, you should give this a try:
Flora grow @ 4mL/gal.
Flora micro @8mL/gal.
Flora Bloom@10mL/gal.
B-52 @ 4mL/gal.

Actual PPM of this mix
N 140
P 72
K 160
Ca 100
Mg 43
S 25

This would be a full-strength mix, so I would suggest diluting it to 50-75%. When I mix my fertilizer, I always mix full strength stock solution, and then add RO water to reach my desired EC value. It's a lot easier than trying to reduce mL/gal. and hoping the concentration works out. If your curious how I did the math, I have a excel spreadsheet that automatically calculates actual ppm values of most of the macro and higher concentration micros. I basically just added your fertilizers to my list, and dicked with the proportions. This is similar to Floranova Grow, optimized with 25% more calcium. Personally, I'd knock the Grow back to 3mL/gal. and add 2mL/gal. of potassium silicate.

Floranova Grow
N 140
P 34
K 166
Ca 80
Mg 30
S 40

 

[TripleCchronic]

This is cal mends break down

As for the potasium silicate will rhini skin do?

 

[pr3tti]

Another problem is that your calcium levels are very high. Your potassium levels are high, but your calcium is about double of what it should be in ratio with potassium and magnesium. As a result, potassium uptake is being reduced to the point of deficiency. The little white dots are from the potassium deficiency.

Wow I think you just solved why adding Potassium Silicate yesterday to my rez seemed to jump my growth rate overnight and no new dots showed up! I thought it was because I lowered my pH to 5.5 finally after having it fixed at 6.1 since sprout.

I had exact same issues with rust spots, brown spots, purple stems, white dots, etc.

Also make sure to mix Potassium Silicate into slightly acidic RO water first then pH again. Then pour into rez after lots of mixing. Don't pour it straight into ur rez!

 

[TripleCchronic]

The issue you where having looked like this?

 

[TripleCchronic]

What percentage of calcium is in the CAL MEND? I see it has 2%N, so I'm guessing it's about 4-5% calcium
For one, you have a sulphur deficiency. That lime green colour is because you only have 7 ppm of sulphur, and typically most nutrient mixes have about 40 ppm in a full strength mix.

Another problem is that your calcium levels are very high. Your potassium levels are high, but your calcium is about double of what it should be in ratio with potassium and magnesium. As a result, potassium uptake is being reduced to the point of deficiency. The little white dots are from the potassium deficiency.

If you're in Veg right now, you should give this a try:
Flora grow @ 4mL/gal.
Flora micro @8mL/gal.
Flora Bloom@10mL/gal.
B-52 @ 4mL/gal.

Actual PPM of this mix
N 140
P 72
K 160
Ca 100
Mg 43
S 25

This would be a full-strength mix, so I would suggest diluting it to 50-75%. When I mix my fertilizer, I always mix full strength stock solution, and then add RO water to reach my desired EC value. It's a lot easier than trying to reduce mL/gal. and hoping the concentration works out. If your curious how I did the math, I have a excel spreadsheet that automatically calculates actual ppm values of most of the macro and higher concentration micros. I basically just added your fertilizers to my list, and dicked with the proportions. This is similar to Floranova Grow, optimized with 25% more calcium. Personally, I'd knock the Grow back to 3mL/gal. and add 2mL/gal. of potassium silicate.

Floranova Grow
N 140
P 34
K 166
Ca 80
Mg 30
S 40

This is exactly the kind of stuff I want to learn about. I have a passion for chemistry and love the nitty gritty details of micro and macro nutrients as well as how they interact in solution and within the plant.

 

[pr3tti]

The issue you where having looked like this?

Yup! Here's what mine looks like now the damage is old.

@TripleCchronic yo we have the same DWC system from Amazon xD

 

[TripleCchronic]

What percentage of calcium is in the CAL MEND? I see it has 2%N, so I'm guessing it's about 4-5% calcium
For one, you have a sulphur deficiency. That lime green colour is because you only have 7 ppm of sulphur, and typically most nutrient mixes have about 40 ppm in a full strength mix.

Another problem is that your calcium levels are very high. Your potassium levels are high, but your calcium is about double of what it should be in ratio with potassium and magnesium. As a result, potassium uptake is being reduced to the point of deficiency. The little white dots are from the potassium deficiency.

If you're in Veg right now, you should give this a try:
Flora grow @ 4mL/gal.
Flora micro @8mL/gal.
Flora Bloom@10mL/gal.
B-52 @ 4mL/gal.

Actual PPM of this mix
N 140
P 72
K 160
Ca 100
Mg 43
S 25

This would be a full-strength mix, so I would suggest diluting it to 50-75%. When I mix my fertilizer, I always mix full strength stock solution, and then add RO water to reach my desired EC value. It's a lot easier than trying to reduce mL/gal. and hoping the concentration works out. If your curious how I did the math, I have a excel spreadsheet that automatically calculates actual ppm values of most of the macro and higher concentration micros. I basically just added your fertilizers to my list, and dicked with the proportions. This is similar to Floranova Grow, optimized with 25% more calcium. Personally, I'd knock the Grow back to 3mL/gal. and add 2mL/gal. of potassium silicate.

Floranova Grow
N 140
P 34
K 166
Ca 80
Mg 30
S 40

I thought a plant needed more gro then bloom in veg?

 

[TripleCchronic]

What percentage of calcium is in the CAL MEND? I see it has 2%N, so I'm guessing it's about 4-5% calcium
For one, you have a sulphur deficiency. That lime green colour is because you only have 7 ppm of sulphur, and typically most nutrient mixes have about 40 ppm in a full strength mix.

Another problem is that your calcium levels are very high. Your potassium levels are high, but your calcium is about double of what it should be in ratio with potassium and magnesium. As a result, potassium uptake is being reduced to the point of deficiency. The little white dots are from the potassium deficiency.

If you're in Veg right now, you should give this a try:
Flora grow @ 4mL/gal.
Flora micro @8mL/gal.
Flora Bloom@10mL/gal.
B-52 @ 4mL/gal.

Actual PPM of this mix
N 140
P 72
K 160
Ca 100
Mg 43
S 25

This would be a full-strength mix, so I would suggest diluting it to 50-75%. When I mix my fertilizer, I always mix full strength stock solution, and then add RO water to reach my desired EC value. It's a lot easier than trying to reduce mL/gal. and hoping the concentration works out. If your curious how I did the math, I have a excel spreadsheet that automatically calculates actual ppm values of most of the macro and higher concentration micros. I basically just added your fertilizers to my list, and dicked with the proportions. This is similar to Floranova Grow, optimized with 25% more calcium. Personally, I'd knock the Grow back to 3mL/gal. and add 2mL/gal. of potassium silicate.

Floranova Grow
N 140
P 34
K 166
Ca 80
Mg 30
S 40

Im getting worried its going to kill my plant as its on %80 of my leaves now. Is it to kate to save her?

 

[iNeedMeds]

I thought a plant needed more gro then bloom in veg?

You're looking at nutrients the wrong way. You see grow, bloom, and micro, and I see this. Micro-large amounts of N and CA, plus it has all the trace elements in it. This is really your base nutrient. Bloom, is a K and P heavy mix, and contains most of your magnesium, and all of your sulfur. The grow is very heavy K, a little medium N, and low P. Now the B-52, has various acids, but it's basically a grow nutrient that has less potassium.

Basically, I put enough micro to set a good amount of Ca. Then, I added bloom to get the magnesium and sulfur required. After that, I was shooting for about 140ppm of nitrogen, while trying to maintain the proper balance of K, Ca, and Mg. Basically, I'm using the B-52 and the grow, to replace using just the grow. That way you get the beneficial acids of the B-52, and the grow supplied the extra K to get it high enough.

If you want to save your plants, I would use this formula at 50% strength. Mix RO water with full strength 50/50, or simply add RO water until the EC is half of full-strength. This is what you could call a low strength flush. When you first apply it, the mobile nutrients at much higher concentrations in the plant, will leach into the solution, likely raising the EC. Don't be alarmed by this, it's normal. Just adjust the pH, and keep adding the 50% strength until you start seeing the EC drop between top ups. When it starts dropping, drain and replace the solution. You can then start at about 60%, and keep adding higher strength nutrients until the EC stops dropping. In veg, I like to see a slight EC drop between feedings, like 0.1. No point in pushing a vegging plant hard.

If your system isn't recirculating, you can try my recipe against the base GH trio recipe for vegetative stage and see which works better for you. GH flora trio nutes are not cannabis specific, but a general use formula. You might have to add epsom salts to the flora trio to prevent magnesium and sulfur deficiency. Mix 12.5grams with RO or distilled water make 1L of concentrate, and apply at 1mL/L to get an extra 15ppm of magnesium and sulfur. That will fix it.

 

[TripleCchronic]

Is my Cal Mend not a good addition for the magnesium?

 

[TripleCchronic]

You're looking at nutrients the wrong way. You see grow, bloom, and micro, and I see this. Micro-large amounts of N and CA, plus it has all the trace elements in it. This is really your base nutrient. Bloom, is a K and P heavy mix, and contains most of your magnesium, and all of your sulfur. The grow is very heavy K, a little medium N, and low P. Now the B-52, has various acids, but it's basically a grow nutrient that has less potassium.

Basically, I put enough micro to set a good amount of Ca. Then, I added bloom to get the magnesium and sulfur required. After that, I was shooting for about 140ppm of nitrogen, while trying to maintain the proper balance of K, Ca, and Mg. Basically, I'm using the B-52 and the grow, to replace using just the grow. That way you get the beneficial acids of the B-52, and the grow supplied the extra K to get it high enough.

If you want to save your plants, I would use this formula at 50% strength. Mix RO water with full strength 50/50, or simply add RO water until the EC is half of full-strength. This is what you could call a low strength flush. When you first apply it, the mobile nutrients at much higher concentrations in the plant, will leach into the solution, likely raising the EC. Don't be alarmed by this, it's normal. Just adjust the pH, and keep adding the 50% strength until you start seeing the EC drop between top ups. When it starts dropping, drain and replace the solution. You can then start at about 60%, and keep adding higher strength nutrients until the EC stops dropping. In veg, I like to see a slight EC drop between feedings, like 0.1. No point in pushing a vegging plant hard.

If your system isn't recirculating, you can try my recipe against the base GH trio recipe for vegetative stage and see which works better for you. GH flora trio nutes are not cannabis specific, but a general use formula. You might have to add epsom salts to the flora trio to prevent magnesium and sulfur deficiency. Mix 12.5grams with RO or distilled water make 1L of concentrate, and apply at 1mL/L to get an extra 15ppm of magnesium and sulfur. That will fix it.

I really want to learn about the diffrent macro and micro nutrient requirements of cannabis so I can better understand whats in my nutrients and how to optimize them. Yoir level of knowledge makes me giddy and I would love to pick your brain.

 

[TripleCchronic]

How close am I to this being a critical issue @iNeedMeds

 

[iNeedMeds]

Is my Cal Mend not a good addition for the magnesium?

There is already adequate amounts of magnesium in that mix.

The three macro cations are K-Ca-Mg. For each stage of growth, you need an approximate ratio between these ions. Typically, in every single nutrient base, you're going to always find Ca and Mg in proportion. As a result, when Ca is low, then Mg also needs to be increased to maintain the ratio.

Basically, you use Ca-Mg additives when your potassium has been increased to the point where it will start locking out the other two cations Ca and Mg.

The reason why these cations need to be in balance, is because plants have a cation-exchange-capacity. Think of it like the plant has the capacity to give up 100 H30+ ions, and attract 100 +ions. K+, Ca+2, Mg+2. To understand the ratios the plant uses these in, you have to consider that K and Ca have relatively similar molar masses, while Mg is about 60.6% of Ca's molar mass.

Let's say per 1mL/L of a solution, there is 40ppm of Ca and 20 ppm of Mg. Are there twice as many ions of Ca than Mg?

See, fertilizers are built around mg/L, and not mol/L.

Ca 9.98 x 10e-4 mol/L
Mg 8.23 x 10e-4 mol/L

K 14.83 x 10e-4 mol/L(Not proper scientific notation, but it's easier if to read)

As you can see, there really is only 20% more Ca ions in this mix than Mg, even though by mass, Mg is only half the concentration.

Now, if there are 100 sites, and these three ionic elements have to share them, how will this occur? For one, Ca and Mg are like fat people on a plane, and require two seats per ion. So you have to divide the K by 2, to make the equivalent charge.

K 29% 58 ions Ionic concentration 45%
Ca 39% 39 ions 30%
Mg 32% 32 ions 25%

As you can see, K occupies the smallest fraction of the CEC of a plant, but twice as many ions are absorbed in that capacity. This is important to understand, because if you increase Ca and Mg with Cal-mend by 25%, you'll see how quickly the K uptake is dropped.

K 21% 42 ions ionic concentration 32%
Ca 49% 49 ions 37%
Mg 40% 40 ions 31%

As you can see, adding Cal-mend to boost Ca and Mg by 25%, resulted in a 38% reduction in K as a result.

Typically, Ca-Mg additives shouldn't really be needed with base nutrients in hydro with an inert medium. It's needed if you're growing with coco, as you will need it to saturate the coco cation exchange sites and offset the naturally high K levels. Most people just use coco nutes now, since they already account for these issues.

However, if you add any product that contains K, then Ca-Mg will also have to be increased to maintain proportion. For example, if you add KSi to protect your plant, then you need Ca-Mg to correct the K-Ca-Mg ratio. People add PK boosters, and once again, you need Ca-Mg to correct the ratio. You might think, WTF is the point of a PK booster if you have to keep the ratio correct? Simple, it's not about pushing more K vs. Ca-Mg, but rather adding enough PK to reduce the N content. This pushes the plants to direct energy to flower production instead of giant green leaves. Honestly, I wouldn't use that Cal-mend as a additive to offset K increases during flower, as it also has lots of N, which isn't ideal. I use cali-magic because it has only 1%N and 5%Ca, which is much better in flower, as higher N Cal-Mag concentrates are really just undoing the benefits of increasing PK to reduce N.

Now, if you have a standalone magnesium deficiency or sulfur deficiency, then you need Magnesium Sulfate, or by it's common name epsom salt. If you want to make some, it's 0.99g to make 1L of concentrate, which can then up your Mg by 20ppm for every 1mL/L. It will also add 26ppm of sulfur. If you're going to mix nutes from powder, you should buy a scale that is accurate to .01g.

 

[TripleCchronic]

There is already adequate amounts of magnesium in that mix.

The three macro cations are K-Ca-Mg. For each stage of growth, you need an approximate ratio between these ions. Typically, in every single nutrient base, you're going to always find Ca and Mg in proportion. As a result, when Ca is low, then Mg also needs to be increased to maintain the ratio.

Basically, you use Ca-Mg additives when your potassium has been increased to the point where it will start locking out the other two cations Ca and Mg.

The reason why these cations need to be in balance, is because plants have a cation-exchange-capacity. Think of it like the plant has the capacity to give up 100 H30+ ions, and attract 100 +ions. K+, Ca+2, Mg+2. To understand the ratios the plant uses these in, you have to consider that K and Ca have relatively similar molar masses, while Mg is about 60.6% of Ca's molar mass.

Let's say per 1mL/L of a solution, there is 40ppm of Ca and 20 ppm of Mg. Are there twice as many ions of Ca than Mg?

See, fertilizers are built around mg/L, and not mol/L.

Ca 9.98 x 10e-4 mol/L
Mg 8.23 x 10e-4 mol/L

K 14.83 x 10e-4 mol/L(Not proper scientific notation, but it's easier if to read)

As you can see, there really is only 20% more Ca ions in this mix than Mg, even though by mass, Mg is only half the concentration.

Now, if there are 100 sites, and these three ionic elements have to share them, how will this occur? For one, Ca and Mg are like fat people on a plane, and require two seats per ion. So you have to divide the K by 2, to make the equivalent charge.

K 29% 58 ions Ionic concentration 45%
Ca 39% 39 ions 30%
Mg 32% 32 ions 25%

As you can see, K occupies the smallest fraction of the CEC of a plant, but twice as many ions are absorbed in that capacity. This is important to understand, because if you increase Ca and Mg with Cal-mend by 25%, you'll see how quickly the K uptake is dropped.

K 21% 42 ions ionic concentration 32%
Ca 49% 49 ions 37%
Mg 40% 40 ions 31%

As you can see, adding Cal-mend to boost Ca and Mg by 25%, resulted in a 38% reduction in K as a result.

Typically, Ca-Mg additives shouldn't really be needed with base nutrients in hydro with an inert medium. It's needed if you're growing with coco, as you will need it to saturate the coco cation exchange sites and offset the naturally high K levels. Most people just use coco nutes now, since they already account for these issues.

However, if you add any product that contains K, then Ca-Mg will also have to be increased to maintain proportion. For example, if you add KSi to protect your plant, then you need Ca-Mg to correct the K-Ca-Mg ratio. People add PK boosters, and once again, you need Ca-Mg to correct the ratio. You might think, WTF is the point of a PK booster if you have to keep the ratio correct? Simple, it's not about pushing more K vs. Ca-Mg, but rather adding enough PK to reduce the N content. This pushes the plants to direct energy to flower production instead of giant green leaves. Honestly, I wouldn't use that Cal-mend as a additive to offset K increases during flower, as it also has lots of N, which isn't ideal. I use cali-magic because it has only 1%N and 5%Ca, which is much better in flower, as higher N Cal-Mag concentrates are really just undoing the benefits of increasing PK to reduce N.

Now, if you have a standalone magnesium deficiency or sulfur deficiency, then you need Magnesium Sulfate, or by it's common name epsom salt. If you want to make some, it's 0.99g to make 1L of concentrate, which can then up your Mg by 20ppm for every 1mL/L. It will also add 26ppm of sulfur. If you're going to mix nutes from powder, you should buy a scale that is accurate to .01g.

Thank you so much for the break down. I love it. So If I want to also add rhino skin what would your recommendation for nute ml/g for each micro gro bloom b 52 and rhino skin? Im also planning to do a flush to reset at 0.

 

[iNeedMeds]

I really want to learn about the diffrent macro and micro nutrient requirements of cannabis so I can better understand whats in my nutrients and how to optimize them. Yoir level of knowledge makes me giddy and I would love to pick your brain.

Well, if you want the knowledge, you have to earn it. I have read probably about 200 or so very dry university studies on hydroponic production. I also enjoy reading the blog articles @ science in hydroponics. Download the hydrobuddy app from the site, and spend some time playing with it. There are some really good studies on strawberries and Tomatoes that can teach you a lot. Also, read books. Sometimes they are free at the library.

I learned because I'm an inventor, and was looking at ways of making machines that help people grow with hydroponics, without needing extensive knowledge to do so. I'm working on some cool stuff to show the community soon.

 

[iNeedMeds]

Thank you so much for the break down. I love it. So If I want to also add rhino skin what would your recommendation for nute ml/g for each micro gro bloom b 52 and rhino skin? Im also planning to do a flush to reset at 0.

4mL/gal Rhino skin
8mL/gal Flora micro
1mL/gal Flora grow
8mL/gal Flora bloom
6mL/gal B-52

135 N
60 P
160 K
100 Ca
31 Mg
20 S
2 Fe
4 Si

This is full-strength. Reduce and build up to where the plants are happy.

 

[TripleCchronic]

Its been 3 days since the flush and nute change and im still getting spots. @iNeedMeds what should I do now. Shouldnt the spots have stopped progressing by now

 

[iNeedMeds]

What is your pH? Is it stable? How are you measuring your pH?