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Stems are turning purple during week 3 of flower

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ilovesluts420

Member
I’m running the Gavita 1700e’s. I had some problems early on in the veg stage with purple stems but now it’s coming back during week 3 flower. Are the lights too strong? They’re at 70% right now. I am slowly bumping up the brightness by 5% a week. Maybe I need more cal mag or nitrogen? Or both?
 
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overbudjet

Active member
Veteran
Purple stem are often du by a lack of mag. Go and buy a bag of epsom salt at drug store and add 1/2 to 1 teaspoon by 5 gal of solution.
 
Medicine Man1

Medicine Man1

Member
ilovesluts420 said:
I’m running the Gavita 1700e’s. I had some problems early on in the veg stage with purple stems but now it’s coming back during week 3 flower. Are the lights too strong? They’re at 70% right now. I am slowly bumping up the brightness by 5% a week. Maybe I need more cal mag or nitrogen? Or both?
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I think you're probably on the right track. A lot of LED users are finding these type of results, and I have a feeling it's something we'll all have to dial to our specific conditions, until someone figures out a formula for how much nutrients plants need in which stage of life, and at what light intensity.

If you're slowly bumping up light intensity, but keeping the same feed level, that might explain the eventual deficiencies you're seeing.
For efficiency sake, you could try turning the light back down slightly, and see if they grow at a better rate, with more even greening. Or you could bump the feed up with the lights, and see if they green up, and grow faster.

I'm going through this fine tuning myself, and wondering how a lower light intensity and feed level will compare to higher levels of both.

I just use Megacrop, pH down, and pool shock, to see how simple I can get away with.

I used to feed the MC at 4 grams per gallon, but I was still getting purple striping and leaf stems here and there, and other signs of deficiency, so I bumped the feed to 5g/gal, and they started looking better.

Well, I bumped the lights up, and eventually they started looking like they were lacking again.

Now the lights are back down, and I'm watching to see how they react.

I've been stubborn, and trying not to add Epsom, but I finally did in a spray bottle, just to try spot spraying a couple particular hungry looking plants. I've only done it recently though, and don't have results for you yet, sorry.

If I don't get satisfactory coloring or smells in the final buds though, I'll probably start adding it to the rez.

Anyway, you could try adding a little of any or all of the suggested nutrients, or you could try turning the light down a little, and see how they react.

Oh, right, you're in the 3rd week of flower... You might not want to bump the food up too high, for too long if you do. They won't want as much of it in a few weeks.
 
Medicine Man1

Medicine Man1

Member
ilovesluts420 said:
I thought cal mag had calcium AND magnesium
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I think he thinks you only need magnesium, which is why he's just recommending the Epsom salts. No sense adding extra calcium if you don't need it. Plus the Epsom would give you a little extra sulphur, for the funky smells... Just my guess though.
 
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ilovesluts420

Member
Medicine said:
I think he thinks you only need magnesium, which is why he's just recommending the Epsom salts. No sense adding extra calcium if you don't need it. Plus the Epsom would give you a little extra sulphur, for the funky smells... Just my guess though.
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I see. So adding epsom salt is a common practice? Never heard of it. So it’s recommended by others? Not saying I don’t trust the fine gentleman who recommended it just would like others to tap in. Anyone else have experience with epsom salt?
 
Medicine Man1

Medicine Man1

Member
Oh yeah, Epsom salts are a common additive. I think the usual dilution is 1tsp/gallon, whether as a foliar spray or in feed water. I'm new to it though, so if other Epsom users have an opinion, chime in. I don't wanna over dose his plants or anything.
 
S

sshz

Well-known member
420giveaway
This can also be from the strain genetics.......which often it is. If the overall leaves look healthy, other than the porple stem- it's probably not going to be an issue
 
Medicine Man1

Medicine Man1

Member
Yeah, could be, especially heavy Cookie/OG/Indica/Chem genetics, which just seem hungrier overall, especially for magnesium.... All those TMV "variegations" that could be solved with a little Epsom salts... Which is why you just add the Epsom... If they're green, but have purple petioles to their fan leaves, and purple stripes on the main stalk, they might just need more mg.

If they're not dark green, yellowing down below, and have purple fan stems, boost your nutrients overall, not just mg...
 
T

tilopa

Member
I just finished a run using LEDs for the first time. The strain was Forbidden Fruit which gets pretty purple at the end. About 3 weeks into flower the buds started getting purple. I was a little concerned at first but then figured maybe it was because of the fuller spectrum of light, I'm using CRI 90. But maybe I should have given them more Mag.

At the end of the day I felt the buds were more purple and had a stronger smell than with my HPS lights. But I think the yield was slightly lower with the LED.
 
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overbudjet

Active member
Veteran
Medicine said:
I think he thinks you only need magnesium, which is why he's just recommending the Epsom salts. No sense adding extra calcium if you don't need it. Plus the Epsom would give you a little extra sulphur, for the funky smells... Just my guess though.
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:woohoo::woohoo::woohoo:
Right on!

Epsom salt is an old grower trick for purple stem .SSHZ is also right some genetic are prone to purple stem .:respect:
 
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ilovesluts420

Member
It’s odd bc I have the same strain in hugos in which the stems are turning purple. I also have the same strain in coco and the stems remain green. I’m noticing the plants like the coco a lot better. Hugo’s are a pain in the ass. Next run I’m going all coco
 
S

sshz

Well-known member
420giveaway
No, LED lights do not cause any kind of nutrient deficiency; purple streaks on stems and petioles are a normal response to exposure to ultraviolet (UV) light.

A rumor was started that LED lights cause magnesium deficiency when people noticed that some plants develop purple petioles (leaf stalks) or streaks on the stems under LED lights, but not under HPS lights. While purple coloration on stems and petioles can be one of the signs of magnesium deficiency in plants, it is also a sign that the plant is producing natural purple pigments (anthocyanin) in response to ultraviolet (UV) light. Many artificial lights (including HPS and most LEDs) don't give off UV light, so plants grown under these lights don't produce this natural pigmentation. Under these UV-lacking lights, purple coloration is often a sign of magnesium deficiency. However, when grown under UV-containing lights or natural sunlight, plants will produce their full range of natural pigmentation-- it is not necessarily a sign of a nutrient deficiency.

The major symptom of magnesium deficiency is usually yellowing, blotchy-looking (chlorotic) leaves, accompanied by purple stems and petioles. When growing under LED grow lights, unless the leaves are chlorotic, purple stems and petioles are not a sign of a magnesium deficiency-- they are a sign of a happy, healthy plant."
 
S

Substitute

Member
sshz said:
No, LED lights do not cause any kind of nutrient deficiency; purple streaks on stems and petioles are a normal response to exposure to ultraviolet (UV) light.

A rumor was started that LED lights cause magnesium deficiency when people noticed that some plants develop purple petioles (leaf stalks) or streaks on the stems under LED lights, but not under HPS lights. While purple coloration on stems and petioles can be one of the signs of magnesium deficiency in plants, it is also a sign that the plant is producing natural purple pigments (anthocyanin) in response to ultraviolet (UV) light. Many artificial lights (including HPS and most LEDs) don't give off UV light, so plants grown under these lights don't produce this natural pigmentation. Under these UV-lacking lights, purple coloration is often a sign of magnesium deficiency. However, when grown under UV-containing lights or natural sunlight, plants will produce their full range of natural pigmentation-- it is not necessarily a sign of a nutrient deficiency.

The major symptom of magnesium deficiency is usually yellowing, blotchy-looking (chlorotic) leaves, accompanied by purple stems and petioles. When growing under LED grow lights, unless the leaves are chlorotic, purple stems and petioles are not a sign of a magnesium deficiency-- they are a sign of a happy, healthy plant."
Click to expand...


Great explanation! Sounds reasonable. My plants are growing under a good amount of UV...and they show natural purple streaks and pigmentation under the light...and they are heatlhy!
 
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ilovesluts420

Member
sshz said:
No, LED lights do not cause any kind of nutrient deficiency; purple streaks on stems and petioles are a normal response to exposure to ultraviolet (UV) light.

A rumor was started that LED lights cause magnesium deficiency when people noticed that some plants develop purple petioles (leaf stalks) or streaks on the stems under LED lights, but not under HPS lights. While purple coloration on stems and petioles can be one of the signs of magnesium deficiency in plants, it is also a sign that the plant is producing natural purple pigments (anthocyanin) in response to ultraviolet (UV) light. Many artificial lights (including HPS and most LEDs) don't give off UV light, so plants grown under these lights don't produce this natural pigmentation. Under these UV-lacking lights, purple coloration is often a sign of magnesium deficiency. However, when grown under UV-containing lights or natural sunlight, plants will produce their full range of natural pigmentation-- it is not necessarily a sign of a nutrient deficiency.

The major symptom of magnesium deficiency is usually yellowing, blotchy-looking (chlorotic) leaves, accompanied by purple stems and petioles. When growing under LED grow lights, unless the leaves are chlorotic, purple stems and petioles are not a sign of a magnesium deficiency-- they are a sign of a happy, healthy plant."
Click to expand...

Whatttt my whole LED life has been a lie...
 
R

roybart

Member
I have 3 Grand Daddy Purple under 6K white LED , never seen UV.
2 have purple stems one doesn't. All in the same bucket same food same light source.
So it can be plant specific for sure..
Like the other's said, if it looks healthy give it love, find something else to get confused about LOL


Also lets not forget, its a weed and can recover from a lot of stuff. Nature provides chaos as part of the life cycle.
Pruning by animals, LST by wind, Hot sun to overcast , humidity can be all over the map. bad air because of a bush fire. Topping by falling limbs, loss of a shade tree or gain of an unwanted shade tree.
All of these variables and still plants survive.
One should only over medicate friends and family. the girls do better on their own unmediated.
 
Medicine Man1

Medicine Man1

Member
sshz said:
No, LED lights do not cause any kind of nutrient deficiency...
Click to expand...


That's a pretty bold statement, and I think many LED growers would respectfully disagree, based on their experiences and observations.



If yours are all healthy, that's awesome- sounds like you found the right combinations of nutrient levels and light intensity for your setup, and ahead of the curve a lot of LED guys are facing!



What nutes do you like to run, and what kind of light coverage?


Since most of the people having these issues have been under different "white" light LEDs, like the OPs, that don't have UV unless you add it,
wouldn't you think his situation would be the beginning stages of deficiency?



I'd agree regarding the blotchy yellow leaves, but it seems like that comes later, after the purple petioles and stem streaking. I guess if he starts seeing that, maybe he can start thinking it might be a deficiency.



Good luck OP! Let us know how they progress.


Pictures and/or more details would help avoid some of these sub conversations we're having. Stuff like what wattage you're running the lights, how far from the plants, what strain the plants in question are, type of medium, feed, etc. A better overall picture for us should get a better, quicker overall answer for you ;-)
 
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