• 🎅 Early Christmas Sale - 25% Off All Seeds 🎄
    Use Coupon Code At Checkout: XMAS25

Is this magnesium deficiency?

105
43
Plant is a clone grown in soil under 18 hours of veg led light.

Does this looks like magnesium deficiency? It’s only on a few tips. Some leaves were a tad crispy too.

Which considering that I’ve given it a few doses of Epson salt it feels like it might be partially locking out magnesium due to PH issues. I have hard well water that is very alkaline. I’ve been adjusting with vinegar. I think this approach sucks and I’m switching to a proper phosphoric acid solution to adjust down.
 
4,919
263
Plant is a clone grown in soil under 18 hours of veg led light.

Does this looks like magnesium deficiency? It’s only on a few tips. Some leaves were a tad crispy too.

Which considering that I’ve given it a few doses of Epson salt it feels like it might be partially locking out magnesium due to PH issues. I have hard well water that is very alkaline. I’ve been adjusting with vinegar. I think this approach sucks and I’m switching to a proper phosphoric acid solution to adjust down.
Whole plant pics. I would suggest citric acid in soil if you feel the need to ph. It's less aggressive. If you were in hydro and needed a stronger more stable acid then I would say yes phosphoric or sulfuric would be a good option.

Personally I feel there is no need to ph nutrients for soil but I won't get into that.

Kinda looks more like it's over watering but I can't really say with only a picture of the leaf.
 
105
43
My well water is around a 6.8 or higher if I don’t PH all my water. Honestly since growing on this water is new to me I’m just doing it because I thought I must. I figured those fancy ph-down products were just phosphoric acid solutions anyhow. It takes me about 4 TABLESPOONS of vinegar per 5-gallon bucket to get it to about 6.2. Seems like it’s a bad idea. Again, I need to do more testing of my soil runoff.

I’m using fabric sided smart pots and they dry out pretty fast so I don’t think I’m overwatering. I only water every 2-3 days and I usually stick my finger in the soil or lift the plant to see if it’s dry first.

You can kinda see it affecting several of the tips of leaves in the group pic. Oddly these problems of dropping leaves, the loss of dark green color near the leaf veins, and increased purpling and redness on leaf stems and stalks have all gotten worse under these industrial 5K led fixtures. I upgraded my veg area to them to save electricity and this way I was able to put both my hid ballasted lights into my flowering room. Something about these lights is either a little deficient or it’s putting an additional nutritional drain on the plant that I’m not compensating for.
 
4,919
263
My well water is around a 6.8 or higher if I don’t PH all my water. Honestly since growing on this water is new to me I’m just doing it because I thought I must. I figured those fancy ph-down products were just phosphoric acid solutions anyhow. It takes me about 4 TABLESPOONS of vinegar per 5-gallon bucket to get it to about 6.2. Seems like it’s a bad idea. Again, I need to do more testing of my soil runoff.

I’m using fabric sided smart pots and they dry out pretty fast so I don’t think I’m overwatering. I only water every 2-3 days and I usually stick my finger in the soil or lift the plant to see if it’s dry first.

You can kinda see it affecting several of the tips of leaves in the group pic. Oddly these problems of dropping leaves, the loss of dark green color near the leaf veins, and increased purpling and redness on leaf stems and stalks have all gotten worse under these industrial 5K led fixtures. I upgraded my veg area to them to save electricity and this way I was able to put both my hid ballasted lights into my flowering room. Something about these lights is either a little deficient or it’s putting an additional nutritional drain on the plant that I’m not compensating for.
Can you take a pic of a plant stock? Are any of the stems drooping or just the leaves?

What are you feeding as far as nutrients and ppm?

Room temps and humidity? Looks like they may be a bit to warm also.

It looks like over or under watering to me.
 
105
43
Standby for additional pics...

As far as stems yea some are definitely a bit less vibrant than they should be imo. I didn’t have these issues under a 400w metal halide. I should mention these two LED fixtures I’m using are not marketed for growing. They are high quality warehouse/convention/arena/natatorium high bay led fixtures. They definitely grow stuff but the 5K spectrum is a bit cooler than I’d like. They are rated at 24,000 lumens each consuming 170 watts and can be placed way too close...I figured that out pretty quick. They might still be too intense at the top of the canopy...might be half the problem...too much light.

Right now the room is about 70 F during the day and as low as 59F at night. Humidity fluctuates between 50%-70% or so. Nutrients are just Fox Farm grow big and big bloom micro nutrient.
 
4,919
263
Standby for additional pics...

As far as stems yea some are definitely a bit less vibrant than they should be imo. I didn’t have these issues under a 400w metal halide. I should mention these two LED fixtures I’m using are not marketed for growing. They are high quality warehouse/convention/arena/natatorium high bay led fixtures. They definitely grow stuff but the 5K spectrum is a bit cooler than I’d like. They are rated at 24,000 lumens each consuming 170 watts and can be placed way too close...I figured that out pretty quick. They might still be too intense at the top of the canopy...might be half the problem...too much light.

Right now the room is about 70 F during the day and as low as 59F at night. Humidity fluctuates between 50%-70% or so. Nutrients are just Fox Farm grow big and big bloom micro nutrient.
Temps are to low. Try for 75-77f day and 65 at night.

Humidity looks good.

How much and often are you feeding?
 
105
43
Temps are to low. Try for 75-77f day and 65 at night.

Humidity looks good.

How much and often are you feeding?
I won’t be able to change the temperature much. Is what it is. Non climate controlled basement. I’ll use a space heater during lights out when it dips below 30F outside to keep it around 50F inside but beyond that it’ll have to do.

My feeding frequency varies a little. Sometimes 5-7 days between feedings but sometimes a little more or I skip entirely. I’d rather grow slower and underfed than stunt it by overfeeding. I’m using the fox farm soil schedule as a rough guide but a little lighter than what they recommend. I put in the big bloom micro nutrients at almost every watering. I’ve put in Epson salts (1 tablespoon per gallon) about twice now.
 

Jack og

JackOG
Staff member
2,275
263
Plant is a clone grown in soil under 18 hours of veg led light.

Does this looks like magnesium deficiency? It’s only on a few tips. Some leaves were a tad crispy too.

Which considering that I’ve given it a few doses of Epson salt it feels like it might be partially locking out magnesium due to PH issues. I have hard well water that is very alkaline. I’ve been adjusting with vinegar. I think this approach sucks and I’m switching to a proper phosphoric acid solution to adjust down.
It’s over watered. And root zone is locking out causing deficiencies. Suggestion, to allow media to dry out. Also ph swings cause a lockout as there is a finite range for certain nutrient availability and plant uptake. Container size is also key, start small and up pot to avoid drowning the root zone. Few charts attached to help ya
 
1,861
263
I think you are getting a lockout that is resulting in a Mg deficiency, but possibly an imbalance of one of the major nutrients...P or K. I remember seeing this last spring on the forum and the issue was identical after switching to LEDs. Your well water doesn't sound too bad, but it's true that too much calcium can lockout magnesium... kind of ironic when you use cal-Mag and it can cause the condition that you are trying to correct.
A foliar dose of Epsom Salts, diluted appropriately, will bypass the roots and will show rapid improvement if Mg was deficient. Fox Farms is also sort of hot for my preferences and it's my opinion that it's high content of nutrients can sometimes interact with other products or conditions, causing somewhat similar problems. What makes diagnosis difficult is that high mineral content can cause high PPM readings, as can high nutrient levels, so it's hard to separate the two using just a PPM meter. A slurry soil test should reveal any Ph problems as well as checking the outflow for excessive nutrients
 
2,026
263
I have no idea and I don’t even know how to find out.
The same way you are testing your nutrient solution; not sure why that is a question.

Also in soil your nutrient pH should be 6.5, not 6.2 so you may be making your soil too acidic with your adjustments. Like @Aqua Man said, I do not check pH when growing in soil, if the microbial life in the soil is working correctly then that will balance the pH in the soil on its own. But I will say that if you are checking your pH with a digital reader and using the Fox Farm nutrient line your pH reading is probably incorrect anyway. Digital meters work by converting the electrical conductivity and salt concentration into a pH reading. In nutrients high in organic matter, like Fox Farm, the ingredients do not always carry a charge, but will still effect pH. Organic molecules are not salts and therefore will often be neutral or if they do have a charge it will not be easily read by digital meters. So I would say ditch the pH readings and the vinegar and just use the nutrients at half the recommended strength.

But as you began to state, plants do respond to LED lighting differently than HID. Typically you do need a bit more calcium in plants when growing under LED. Also the LED units do not heat up the plants leaf surfaces as much so that changes things too, typically a room running LED needs to be kept warmer than a room running HID. So while your 70 degree temps are ok when using HID, they may be too low for good healthy plant growth under the LED.
 
943
243
I think you are getting a lockout that is resulting in a Mg deficiency, but possibly an imbalance of one of the major nutrients...P or K. I remember seeing this last spring on the forum and the issue was identical after switching to LEDs. Your well water doesn't sound too bad, but it's true that too much calcium can lockout magnesium... kind of ironic when you use cal-Mag and it can cause the condition that you are trying to correct.
A foliar dose of Epsom Salts, diluted appropriately, will bypass the roots and will show rapid improvement if Mg was deficient. Fox Farms is also sort of hot for my preferences and it's my opinion that it's high content of nutrients can sometimes interact with other products or conditions, causing somewhat similar problems. What makes diagnosis difficult is that high mineral content can cause high PPM readings, as can high nutrient levels, so it's hard to separate the two using just a PPM meter. A slurry soil test should reveal any Ph problems as well as checking the outflow for excessive nutrients
Jimster how do you feel the LED affects the calcium and magnesium uptake and mobility ? I’m thinking it’s even magnified more for auto flowers? But I def think the light affects the need and the uptake . What’s ur thoughts ?
 
943
243
The same way you are testing your nutrient solution; not sure why that is a question.

Also in soil your nutrient pH should be 6.5, not 6.2 so you may be making your soil too acidic with your adjustments. Like @Aqua Man said, I do not check pH when growing in soil, if the microbial life in the soil is working correctly then that will balance the pH in the soil on its own. But I will say that if you are checking your pH with a digital reader and using the Fox Farm nutrient line your pH reading is probably incorrect anyway. Digital meters work by converting the electrical conductivity and salt concentration into a pH reading. In nutrients high in organic matter, like Fox Farm, the ingredients do not always carry a charge, but will still effect pH. Organic molecules are not salts and therefore will often be neutral or if they do have a charge it will not be easily read by digital meters. So I would say ditch the pH readings and the vinegar and just use the nutrients at half the recommended strength.

But as you began to state, plants do respond to LED lighting differently than HID. Typically you do need a bit more calcium in plants when growing under LED. Also the LED units do not heat up the plants leaf surfaces as much so that changes things too, typically a room running LED needs to be kept warmer than a room running HID. So while your 70 degree temps are ok when using HID, they may be too low for good healthy plant growth under the LED.
Good info ! Care to take a shot at the LED /calcium question I just posted to @Jimster ?
 
2,026
263
Good info ! Care to take a shot at the LED /calcium question I just posted to @Jimster ?
Typically under LED plants do seem to need more calcium to remain healthy, but as was stated earlier a Ca toxicity can lock out magnesium. I prefer to use separate calcium and magnesium supplements to avoid this issue. Its a fine line we tread, but I would always rather have less than more going to a plant. The only real effect the light will have on the plants nutrient use is a more intense light will increase the plants metabolism as it tries to grow to its fullest potential and a plant with too little lighting will use far less nutrients. Ultimately we want to find balance in our plants and our nutrient regimen. The only reason under LED you would need more calcium as opposed to HID lighting is that there is a more broad light spectrum with LED keeping certain internal processes going than if we work under lights with a more narrow spectrum, such as HPS.

As for mobility, lighting cannot change mobility of an element through the plant. There are some elements such as calcium that is immobile, it has to be imparted into the cell at inception, it cannot be moved into the cell one it has developed. Other plants are mobile and are moved through plant cells. An internet search should get you all the info you need on which ones are mobile and which ones are not.
 
943
243
That’s great! Thanks for the thought ! I have stRted the search but a lot of the quality information is in a foreign language to me! Lmao I’m an intelligent person (I think) but botany is whole career ! I’m just really getting started but I don’t like it when I don’t know shit!! So I jump in head first! And feel I have to know lots more.
This forum allows me to ask people such as your self who obviously are well versed!!! And get responses in more layman terms. So I understand how it works, but not really. Thank you great help!
P.S. what do you use as supplemental calcium ? Magnesium?
 
2,686
263
Can u explain the “mobile” part ? And does the LED enhance its mobility ? Or force it to attach to other molecules?
@Smoking Gun pretty much nailed it.

Mobile nutes Like N or Mg will move in the plant. Meaning if new growth is Mg deficient it will pull Mg out of the lower leaves and move it towards the new growth. So if you run into a Mg def. it will show up on older growth first at the bottom of the plant before newer growth at the top of the plant. Most Macro's and Mg are mobile. Micro's and generally Ca (a little mobile) wont move and pop up in the new growth at the top of the plant. If it's micro's most likely its a PH issue or a watering issue. Specially if using complete nutes or amended soil. Micro def is rare but lockout is more common from the above reasons.

there ya go
 
4,919
263
Great info I still feel it's over or under watering. I would very much lean to over watering.

Those cold temps are also going to slow nutrient uptake and those pots look like they are directly on the floor probably making for very low root zone temps. Switching back to his that provides some IR to warm the leafs may help???
 

Latest Cannabis Seeds

Sundae Cookies
Sold out

Sundae Cookies

Divine Genetics
Sundae Driver x GMO Cookies
12
Feminized
New
$200.00
Sunset Sherbet S1
Sold out

Sunset Sherbet S1

Divine Genetics
Girl Scout Cookies x Pink Panties
12
Feminized
New
$200.00
Strawberry Sorbet
Sold out

Strawberry Sorbet

DNA Genetics
Heirloom Swiss Sativa x Sorbet
6
Feminized
Limited
$85.00
Sorbet Stash
Sold out

Sorbet Stash

DNA Genetics
Headstash x Sorbet
6
Feminized
Limited
$85.00
Top