Defficiency? Gold/Yellow looking blotches on leaves! Calcium? Magnesium?

Hey there,

I don't want to jump to conclusions, though looking at photos online, it appears that I might have a calcium deficiency? Would love to hear your thoughts on this!

I am currently using Professor's Nutrients - Go Roots, Grow Fast, Go Green & A&B, as well as Silika Magic.

Would appreciate some input so I can adjust accordingly. My current nutrients should be a "all you need" product, though I don't think the "Go Green" is providing as much Calcium/Magnesium, would it be beneficial to add something like a CalMag, or should I up my Go Green?

What's your environmental readings at as far as temp and humidity? Also do you know the pH your water if so what's the reading?

SkunkDawgMike said:

What's your environmental readings at as far as temp and humidity? Also do you know the pH your water if so what's the reading?

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Hey man,

Temps are sitting around 22 degrees celcius, humidity sits above 55% - usually around 55-75%.

pH of the water when I make the nutrient solution is usually 5.8/6, though I've noticed the pH of my nutrient solution was slowly rising over the course of a couple of days - it reached approximately 6.8pH after 2/3 days sitting there. It is aerated with two stones, however, the container is see-through and not dark, so I'm not sure if that's effecting and creating a rise in pH. When I come back to the solution, I add a bit more pH down.

I, however, noticed little gold blotches on the bottom (old growth) leaves, before re-adjusting the pH down after the above senareo.

I'd say more than half the plants are extremely happy and have strong growth, though there are a few that are taking off slowly. They're all the same strain (popped from seeds), though I assume they're all different pheno's.

To summarize, I try to keep my pH around 5.5-6.5. I read out there that it's fine to let the solution drift up to 7pH.

Keen to hear your thoughts.

I had a look at the babies this morning, and they don't appear to be getting any "worse" than the above photos, though I'll re-assess later today after lights-out, and see how they look once they wake up from their nap.

I also may add, I've only now just added an exhaust fan to the tent as I've been extremely busy lately. The fan was added just the other night. The humidity before installing the exhaust fan was sitting a bit higher, sometimes it would climb to over 85%. and slightly higher temps, around 24-28 degrees C.

The little golden blotches started appearing about a week ago, though they've only very slowly gotten bigger and more noticeable.

In my opinion I'd correct the pH swing issue and then just watch and see the results before you add or subtract anything from your normal routine , pH of the Media your in?

SkunkDawgMike said:

In my opinion I'd correct the pH swing issue and then just watch and see the results before you add or subtract anything from your normal routine , pH of the Media your in?

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Hey mate, thanks for getting back in touch.

These babies are still very young, and have not been fed nutrients out of pH range. The issue also arose before any noticeable pH issues, though it still definitely could be an issue related to pH as you say.

Any idea if having my nutrients aerated in a clear tank will cause pH to slowly rise? Could there be algae or something growing in the tank that I can't see with the naked eye? The tank is a blue "water" tank, which is see-through, so light can penetrate the container. I do have a proper nutrient resi (light proof, almost), though I am yet to set that up as I'm not needing that much water just yet.

I've got no idea why the pH is rising, and I guess it's probably just a rookie mistake/oversight.

Yoo my bad was a bit smoked out earlier and neglected to mention try cutting the silica from your res if you add it , silica tends to raise pH from my experience , could be cause of the rise in the res

what lights are you running? how close?

SkunkDawgMike said:

Yoo my bad was a bit smoked out earlier and neglected to mention try cutting the silica from your res if you add it , silica tends to raise pH from my experience , could be cause of the rise in the res

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Hey man,
Thanks for getting back in touch.

I can definitely try to give that a go and remove the silica. I was told by my local Hyro guy that silica is a "must" to help strengthen the plant... Quite conflicting. Should I try to feed the plant separately with silica, if so, how would I go about that?

I plan to have the plants on an automatic feeding system, so I don't want to have to mess around with a rising pH, though I'll definitely remember to skip on the silica when I make the next res. Could this possibly be the reason why the pH keeps raising?

toastedleaf said:

what lights are you running? how close?

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Hey man, running home-made lights. CXB3590 chips, some are running at 50W, others at about 85W. I haven't measured the distance of the light, though I tend to move them up/down depending on how the plants react, as to ensure they don't get too stressed. Is it best to keep them farther away while they're smaller plants? They're still babies, so it could be possible that the light intensity is causing too much stress, however, the issue with the leaves started on the bottom, older leaves, and not the top, newer leaves, so I'm not sure if it is light stress?

RockStonedJesus said:

Hey man,
Thanks for getting back in touch.

I can definitely try to give that a go and remove the silica. I was told by my local Hyro guy that silica is a "must" to help strengthen the plant... Quite conflicting. Should I try to feed the plant separately with silica, if so, how would I go about that?

I plan to have the plants on an automatic feeding system, so I don't want to have to mess around with a rising pH, though I'll definitely remember to skip on the silica when I make the next res. Could this possibly be the reason why the pH keeps raising?


Hey man, running home-made lights. CXB3590 chips, some are running at 50W, others at about 85W. I haven't measured the distance of the light, though I tend to move them up/down depending on how the plants react, as to ensure they don't get too stressed. Is it best to keep them farther away while they're smaller plants? They're still babies, so it could be possible that the light intensity is causing too much stress, however, the issue with the leaves started on the bottom, older leaves, and not the top, newer leaves, so I'm not sure if it is light stress?

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i just went through a very similar experience( you are welcome to check out my journal). If you believe your nutes and ph are all dialed in it could be that the lights are just too intense. Dimming them down and raising them worked for me. I know each situation can be different but this is all i needed to fix my problem. Good Luck!

that looks a lot like the damage you get from large ph fluctuations...
you didn't say what medium you're growing in, if that's coco, you want to be at about 5.8 in flower. the ph will naturally rise in your pots as the plant uses what it needs, but it will come back when you add fresh water, preferably daily. i don't even use a res, i grow in hempy buckets and make fresh feed daily. the guys that say to ph at different phs so the plant doesn't get deficiencies are goofy, ph rises and falls on its own, no need to change it on your own, that's just you adding complications to a system that's already working...
if that's dirt...6.5...all day, every day
a few of those spots could be from calcium deficiency, but stabilize your ph first, and see if they go away before you add a load of calmag

toastedleaf said:

i just went through a very similar experience( you are welcome to check out my journal). If you believe your nutes and ph are all dialed in it could be that the lights are just too intense. Dimming them down and raising them worked for me. I know each situation can be different but this is all i needed to fix my problem. Good Luck!

View attachment 4930513

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Hmm, interesting. I've raised the lights a bit more to see if this helps them at all. Definitely looks very similar in terms of where the discoloration is happening on your plants vs mine - so I'll raise the lights and see if that helps them at all.

Roger A. Shrubber said:

that looks a lot like the damage you get from large ph fluctuations...
you didn't say what medium you're growing in, if that's coco, you want to be at about 5.8 in flower. the ph will naturally rise in your pots as the plant uses what it needs, but it will come back when you add fresh water, preferably daily. i don't even use a res, i grow in hempy buckets and make fresh feed daily. the guys that say to ph at different phs so the plant doesn't get deficiencies are goofy, ph rises and falls on its own, no need to change it on your own, that's just you adding complications to a system that's already working...
if that's dirt...6.5...all day, every day
a few of those spots could be from calcium deficiency, but stabilize your ph first, and see if they go away before you add a load of calmag

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Hey, sorry - totally forgot. Growing in Coco/perlite mix (70/30).
You say 5.8 during flower, what would be your recommendation for veg? The nutrients I have suggest anywhere between 5.5 and 6.5 according to their regime. I do adjust my pH down, though I've noticed my nutrient resivour slowly creeps back up. I haven't fed them to full run-off yet, since they're still so young and not drinking much, I didn't want to over-water them. I hand feed them, if that makes any difference at all. They don't seem to be getting any worse in terms of new growth, so hopefully it's just a small bump in the road. Unfortunately, I don't have the ability to make a nutrient solution daily, especially with working full time and having other commitments, so mixing a solution once every 3/4 days is ideal. Once I setup the auto feeding system, I plan to make a tank to last at least once a week.

The nutrients I am currently using should be fine for a week, as mentioned in their feeding program.

I did call the company that manufactures the silica, and they did advise that the pH will rise when added to the mixture, however, they said it has "buffers" in it, so it should lock-in the pH and it shouldn't drift back up.

After discussion with another member, as well as @toastedleaf 's suggestion, I believe they may be getting light burnt. I'll keep an eye on the lights and move them up/down according to how the plants react.

RockStonedJesus said:

Hey mate, thanks for getting back in touch.

These babies are still very young, and have not been fed nutrients out of pH range. The issue also arose before any noticeable pH issues, though it still definitely could be an issue related to pH as you say.

Any idea if having my nutrients aerated in a clear tank will cause pH to slowly rise? Could there be algae or something growing in the tank that I can't see with the naked eye? The tank is a blue "water" tank, which is see-through, so light can penetrate the container. I do have a proper nutrient resi (light proof, almost), though I am yet to set that up as I'm not needing that much water just yet.

I've got no idea why the pH is rising, and I guess it's probably just a rookie mistake/oversight.

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Sounds more like low ph to me.

Southernontariogrower said:

Sounds more like low ph to me.

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Thanks for getting back in touch.
I'll keep a close eye on pH, however, I am pH'ing my nutrient mix before feeding to ensure a correct pH. I am using Bluelab pH and EC pens, and they're both properly calibrated. If it's a low pH issue, what would be your recommended pH levels? The nutrient brand I am using recommends 5.5 - 6.5. Keen to hear your thoughts!

RockStonedJesus said:

Thanks for getting back in touch.
I'll keep a close eye on pH, however, I am pH'ing my nutrient mix before feeding to ensure a correct pH. I am using Bluelab pH and EC pens, and they're both properly calibrated. If it's a low pH issue, what would be your recommended pH levels? The nutrient brand I am using recommends 5.5 - 6.5. Keen to hear your thoughts!

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Sounds like everything ok but not, if meter is faulty you could be feeding much lower. I havent used ph down since going back to drops from not taking care of meter properly. It wasnt that old but didnt have in solution. My meter read 3 pts high. So my 5.4 was 2.4 and 6.4 was 3.4. Plants were yellow necrotic purple red etc. Hope this helps.

Southernontariogrower said:

Sounds like everything ok but not, if meter is faulty you could be feeding much lower. I havent used ph down since going back to drops from not taking care of meter properly. It wasnt that old but didnt have in solution. My meter read 3 pts high. So my 5.4 was 2.4 and 6.4 was 3.4. Plants were yellow necrotic purple red etc. Hope this helps.

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Thanks for your input man, much appreciated.
My pens are calibrated with a known pH solution, as well as a known EC solution (both Bluelab branded).
My overall pH is high once all the nutes are mixed due to the Silica - I called the company that manufactures the silica, and they advised that it does raise the pH of the nutrient solution significantly, so that explains why my resi has such a high pH. I do use pH down to bring it back down, though it is strange how it starts to rise over 1-3 days. Another member did point out to me that the pH is known to rise over the first 24 hours, so I think I might write down what the pH is once all nutes are mixed, and what pH I bring it down to. Check the solution again in 24 hours, re-adjust if necessary, and check again 24 hours later (48 hours after solution is made), to see if it drifts back up again. If it drifts back up, then there's something going on with my resi (algae/bacteria?).

For now, I'll tinker my light height and bring them up to see if this helps the leaves. I'll also be sure to keep a close eye on all nutrient aspects, EC/pH. I'll keep ya'll posted if there are any new issues developing!

RockStonedJesus said:

Hmm, interesting. I've raised the lights a bit more to see if this helps them at all. Definitely looks very similar in terms of where the discoloration is happening on your plants vs mine - so I'll raise the lights and see if that helps them at all.


Hey, sorry - totally forgot. Growing in Coco/perlite mix (70/30).
You say 5.8 during flower, what would be your recommendation for veg? The nutrients I have suggest anywhere between 5.5 and 6.5 according to their regime. I do adjust my pH down, though I've noticed my nutrient resivour slowly creeps back up. I haven't fed them to full run-off yet, since they're still so young and not drinking much, I didn't want to over-water them. I hand feed them, if that makes any difference at all. They don't seem to be getting any worse in terms of new growth, so hopefully it's just a small bump in the road. Unfortunately, I don't have the ability to make a nutrient solution daily, especially with working full time and having other commitments, so mixing a solution once every 3/4 days is ideal. Once I setup the auto feeding system, I plan to make a tank to last at least once a week.

The nutrients I am currently using should be fine for a week, as mentioned in their feeding program.

I did call the company that manufactures the silica, and they did advise that the pH will rise when added to the mixture, however, they said it has "buffers" in it, so it should lock-in the pH and it shouldn't drift back up.

After discussion with another member, as well as @toastedleaf 's suggestion, I believe they may be getting light burnt. I'll keep an eye on the lights and move them up/down according to how the plants react.

Click to expand...

to be as accurate as a stoner can be, i ph to 5.75 in veg, and 6-6.2 in flower, to better use the available ranges of nutrients at the proper times. if you start off at 6.1, it will rise to about 6.5-6.6 in a day of healthy growth, putting you in the sweet spots for P, K, sulfur, magnesium, C.....

your res ph should be fairly stable, might rise slowly over 3 or 4 days, but it shouldn't take much to correct it. Silica will indeed raise you ph, but i only use it maybe two or three times in a plants life. i'll give it to them for a couple of feedings when they're young, and once when they start stretching when they go into flower...i'm not sure they actually need it then, but it seems to make them a little more able to support the weight of buds, and not just have whole branchs hanging down under the weight

Roger A. Shrubber said:

to be as accurate as a stoner can be, i ph to 5.75 in veg, and 6-6.2 in flower, to better use the available ranges of nutrients at the proper times. if you start off at 6.1, it will rise to about 6.5-6.6 in a day of healthy growth, putting you in the sweet spots for P, K, sulfur, magnesium, C.....

your res ph should be fairly stable, might rise slowly over 3 or 4 days, but it shouldn't take much to correct it. Silica will indeed raise you ph, but i only use it maybe two or three times in a plants life. i'll give it to them for a couple of feedings when they're young, and once when they start stretching when they go into flower...i'm not sure they actually need it then, but it seems to make them a little more able to support the weight of buds, and not just have whole branchs hanging down under the weight

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Thanks for your advice, I will definitely keep this into consideration. I'll have to keep tinkering around with the pH drifting up and figure out what works best for me. I assume it could possibly be due to all the chemicals in the tap water precipitating out over the first 24-48 hours?

For all those wondering, I raised the lights slightly higher, removed the old gold-barred leaves, and all seems well thus far, no new issues developing on the leaves. They're growing at a nice rate so far, so fingers crossed I don't run into any major speed bumps along the way.

I might have to start a grow journal thread for ya'll to follow. Here are some update pics. Hope this helps.