Just a note - Mg def seems to take a while to show up - but when it does, it advances quickly. I would address it as soon as you see indications.
Super Silver Haze, Amsterdam Genetics: 60x60cm 2x2ft, DWC, 250w HPS, T.A. GHE, ScrOG
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- #142
PlanetJ
Well-Known Member
Cruising along here today, need to get that epsom applied I think, tho I'm not entirely sure on what I see vs what I read when I search for Mg deficiency in cannabis. My pictures dont get the colours right, regardless of when I take em.
I can definitely see it getting worse.
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- #144
PlanetJ
Well-Known Member
Yah, today I will change the res, I have been topping it off for the complete flowering period to date. It's about time.
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- #145
PlanetJ
Well-Known Member
So, res changed, pH'ed at 6.22 and ready to rock and roll again I hope. @FelipeBlu would you still advice extra Epsom or first wait and see what she does?
I think that 1g/gal Epsom can only help the situation - it certainly won’t hurt.
I don't recommend Espon salt to much can hurt a plant. Make them lock up. But that's me. Sorry had to Chime in on that planetj. Plus no none benefit from it ether that I ever know. Farmers back in day add magnesium sulfate to their fields and it was a myth it did something other than kill everything in the fields .
I would agree - too much of anything - even water - can hurt the plant. Magnesium is seldom deficient in natural soils - so farmers adding it without knowing the soil chemistry could cause issues.
But 1 to 2g/gal of Epsom salt added to a hydroponic reservoir is hardly too much for a plant of that age. Especially if the current dose of Mg in the base nutrients is low (in my opinion). And it‘s obvious (to me) that the plant is suffering from an advancing Mg deficiency.
As always, it is the individual grower’s decision. I am simply sharing my knowledge and experience. And a toke..
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- #149
PlanetJ
Well-Known Member
I added 4.5g of epsom salt to 22L of water which made EC rise from 1.74 to 1.85 or so, and I had to pH down a bit afterwards. Quite a bit.
This is less than a gram per Gallon.
Lets see what that does, and else the res is changed quick enough if I get mystery issues all of a sudden.
This is less than a gram per Gallon.
Lets see what that does, and else the res is changed quick enough if I get mystery issues all of a sudden.
mAg deffiencey . Like 3 rd stage looks like can't tell with color of the lights
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- #151
PlanetJ
Well-Known Member
Thats what I was thinking myself, but adding some extra calmag and making sure pH is not too high or low, didnt help over past few days. I'm assuming lockout through imbalance in mix due to recycling res.
Its a bit meh, as the dificiency is forming on the middle fanleaves, not the top, not the bottom .. so it's basically sticking its tongue out. I have been thinking Mn, except that the pale green is nowhere to be found on my leaves.
Different deffiencey targets certain part plant first. Like potash will be tips. Cal mag will do one certain leaf first so forth. I forgot most but u can see on plants something wrong they will give u a hint before they color and such. I look and just watch mine few times a day so I know exactly what they are doing and when I look and something different. I start looking. One fan leaf can drop them another u get to learn the plant that way easyier
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- #153
PlanetJ
Well-Known Member
Not quite sure yet if the deficiency is treated now. The interesting thing is that it all seems to be on the 2nd node from the top. Not above, not below.
Made some better pictures, or at least, I tried to.
The pH was quite high again, almost touching 7, so brought that back down. EC after water refill was still 1.84. I did measure EC not a long while after adding the Epsom, so it might have still been rising, otherwise, she didnt use nutes.
Lets check that again tomorrow, if unchanged, I will res-change again I think. Suggestions?
Made some better pictures, or at least, I tried to.
The pH was quite high again, almost touching 7, so brought that back down. EC after water refill was still 1.84. I did measure EC not a long while after adding the Epsom, so it might have still been rising, otherwise, she didnt use nutes.
Lets check that again tomorrow, if unchanged, I will res-change again I think. Suggestions?
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- #155
PlanetJ
Well-Known Member
I know, but I thought it looked like Cal myself. I since changed res and added ~0.8g Epsom salt per L of water. Took EC from 1.74 to 1.85.
Question FelipeBlu! And hopefully one that won't siderail anything (it's more a personal question). In a situation like this, how much Epsom would have to be added before an imbalance happens?
I know there's a ratio that has to be maintained with the calcium, but i was never too comfortable with the ratio understanding.
And I also know you're probably one of the best people on here who I could ask (I'd recommend taking any advice from FelipeBlu as golden...99.9% of the times).
And PlanetJ - you're getting close, going to be some juicy nugs! And also, that question wasn't asked in relation to your grow. I don't think you're anywhere near the imbalance
Hola Rexer
Like you, I have seen a lot of debate regarding the K-Ca-Mg ratios. I think that there is no one answer - it likely depends on the type of crop - and in the case of cannabis, the strain and even phenotype. I can only say what has worked for me - and even in my experience, a mid-grow boost of Mg has often been necessary.
Generally speaking, I aim for a ratio around 4-2-1. This means that at a maximum K of about 250ppm, max Ca would be around 125-130ppm and max Mg would be about 70. The thing is - Ca uptake greatly depends on transpiration rate - and with my typical low humidity, transpiration can be extreme. I think this is why I have to boost Mg - especially after stretch.
And I think it is probably better to exceed the Ca and Mg portions of the ratio some - than to increase K too much in an attempt to maintain an absolute ratio. In my experience, it is an unusual strain that will tolerate much over 300ppm K without distress.
Also, as I stated before - it is very easy to get behind on Mg - once you see obvious symptoms, you are already chasing after a deficiency. In that case, it is better to boost Mg up to 100ppm or apply via foliar (not easy during flowering).
FYI, each g/gal of Epsom salt provides 26ppm Mg. Of course, this would be in addition to whatever your base nutrients provides - so don’t forget to factor that in.
I hope this is helpful.
And there's the knowledge drop I was looking forHola Rexer
Like you, I have seen a lot of debate regarding the K-Ca-Mg ratios. I think that there is no one answer - it likely depends on the type of crop - and in the case of cannabis, the strain and even phenotype. I can only say what has worked for me - and even in my experience, a mid-grow boost of Mg has often been necessary.
Generally speaking, I aim for a ratio around 4-2-1. This means that at a maximum K of about 250ppm, max Ca would be around 125-130ppm and max Mg would be about 70. The thing is - Ca uptake greatly depends on transpiration rate - and with my typical low humidity, transpiration can be extreme. I think this is why I have to boost Mg - especially after stretch.
And I think it is probably better to exceed the Ca and Mg portions of the ratio some - than to increase K too much in an attempt to maintain an absolute ratio. In my experience, it is an unusual strain that will tolerate much over 300ppm K without distress.
Also, as I stated before - it is very easy to get behind on Mg - once you see obvious symptoms, you are already chasing after a deficiency. In that case, it is better to boost Mg up to 100ppm or apply via foliar (not easy during flowering).
FYI, each g/gal of Epsom salt provides 26ppm Mg. Of course, this would be in addition to whatever your base nutrients provides - so don’t forget to factor that in.
I hope this is helpful.
. And I love how you were kind enough to not point out I had forgotten to include the K part of the ratio 
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- #159
PlanetJ
Well-Known Member
Impossible .. I love this kind of discussion, feel free to always start one in my journals, happy to learn along!
Right, now things are starting to make sense .. I feel a bit dumb now tbh. One can have more than one deficiency showing, and I think you spotted the one that had to be treated first. I added a very modest amount, and I believe it's looking better now. Its a bit hard to tell what did it, but the Epsom certainly didnt hurt.
(Tho it did give my pH a kick up) Journal update in a bit.
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- #160
PlanetJ
Well-Known Member
I believe we are back on track here, tho another application of Epsom might be required from the explanation above.
Thanks for the great added value to this journal
Bit of pH-, some water, otherwise nothing done. EC dropped from 1.85 to 1.82.
Thanks for the great added value to this journal
Bit of pH-, some water, otherwise nothing done. EC dropped from 1.85 to 1.82.
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