Growth turns Purple, and Gnarly at flowering onset. Ruining plants completely.

Anyone have any idea what this is. A buddy on another forum posted these photos, and my friend where I live is having the EXACT same problem, and has had this problem for the last 4 years, ruining hundreds of plants.

Im thinking its some kind of Cal/Mag, and maybe also sometimes being wet to long.

These are outside, and the same inside plants dont do this, and are on a regular watering/feed schedule vs outside.

Medium is Promix BX. Food. 19-19-19..0-0-60 Granular. Extra Calcitic/Dolomitic Lime.

I believe the nutrients are used up now, and may have some kind of Cal/Mag problem.

But am open to all suggestions.

Thanks in advance.


This is NOT COLD, or BURN.

Just fed them 15.5-0-0 x 4-20-39. Magnesium, and Azomite to see if this helps.

Hi, i found this article on another site, it may help you out, looks a little like you're pics, hope you get it sorted, goodluck.


Problem: A boron deficiency in cannabis is relatively rare unless a plant is underwatered or in a really dry environment, and is usually accompanied by other types of nutrient or pH problems that appear as problems with the leaves.
The first signs of a cannabis boron deficiency is abnormal or thick growth tips along with brown or yellow spotting on new leaves.

With a boron deficiency, upper cannabis leaves display abnormal and/or slowed growth. Growing tips may not grow properly, may display twisted growth, and may die off. New leaves may wrinkle or curl.
Plant roots can also be affected by a boron deficiency, showing unhealthy or slow growth. Stems may become rough or hollow. Boron deficiencies are more likely to appear when a plant is underwatered or experiencing very low humidity (very dry air).
A plant with a boron deficiency may look like it has a calcium deficiency because boron is needed for the plant to properly use calcium. New growth is affected the most, and may look like it’s been burnt or scorched. A boron deficiency is often accompanied by an apparent potassium or nitrogen deficiency, as these nutrients are needed for the plant to use boron.

Solution for Boron Deficiency in Cannabis
Note: Sometimes a cannabis boron deficiency (like all deficiencies) can be triggered by stressful conditions and may clear up on its own after the period of stress is over.
1.) Use Good Sources of Nutrients
Most cannabis growers don’t need to add more nutrient. In fact, most growers have actually already given plenty of boron to their cannabis plants, whether they meant to or not. If you’re using quality soil or cannabis-friendly nutrients, you probably don’t need to worry about adding more boron. Boron deficiencies are generally more likely to appear when a grower is using heavily filtered or reverse osmisis (RO) water to feed plants, since boron is found in most tap water, but that’s actually not the most common reason growers see boron deficiencies in their cannabis plants! As long as you’re giving your plants a good source of nutrients, you probably need to…
2.) Adjust pH to Correct Range
But the reason most growers see boron deficiencies is because boron is best absorbed at lower pH ranges. When the pH gets too high, your plant may exhibit signs of a boron deficiency even if it’s physically there near the roots.
Learn how to manage your pH when growing cannabis.
In soil, boron is best absorbed by the roots in the 6.0 – 6.5 pH range (in soil, it’s generally recommended to keep the pH between 6.0 – 7.0, but boron specifically tends to be best absorbed below 6.5).
In hydro, boron is best absorbed by the roots in the 5.5 – 6.2 pH range (in hydro, it’s generally recommended to keep the pH between 5.5 – 6.5, but boron specifically tends to be best absorbed below 6.2).
3.) Give Plants Enough Moisture
Boron is not absorbed well if there isn’t enough moisture, for example if plant is underwatered or humidity is very low (below 25% relative humidity in the air). Proper watering practices will help prevent underwatering, and a humidifier may be needed to achieve the best growth if your grow room is very dry.
4.) Watch Leaves for Recovery
If you suspect your growing cannabis plant has a boron deficiency, flush your system with clean, pH’d water that contains a regular dose of cannabis-friendly nutrients. Old damaged growth will likely not recover. Watch plant over next few days to make sure Boron Deficiency


Problem: A boron deficiency in cannabis is relatively rare unless a plant is underwatered or in a really dry environment, and is usually accompanied by other types of nutrient or pH problems that appear as problems with the leaves.
The first signs of a cannabis boron deficiency is abnormal or thick growth tips along with brown or yellow spotting on new leaves.

With a boron deficiency, upper cannabis leaves display abnormal and/or slowed growth. Growing tips may not grow properly, may display twisted growth, and may die off. New leaves may wrinkle or curl.
Plant roots can also be affected by a boron deficiency, showing unhealthy or slow growth. Stems may become rough or hollow. Boron deficiencies are more likely to appear when a plant is underwatered or experiencing very low humidity (very dry air).
A plant with a boron deficiency may look like it has a calcium deficiency because boron is needed for the plant to properly use calcium. New growth is affected the most, and may look like it’s been burnt or scorched. A boron deficiency is often accompanied by an apparent potassium or nitrogen deficiency, as these nutrients are needed for the plant to use boron.

Solution for Boron Deficiency in Cannabis
Note: Sometimes a cannabis boron deficiency (like all deficiencies) can be triggered by stressful conditions and may clear up on its own after the period of stress is over.
1.) Use Good Sources of Nutrients
Most cannabis growers don’t need to add more nutrient. In fact, most growers have actually already given plenty of boron to their cannabis plants, whether they meant to or not. If you’re using quality soil or cannabis-friendly nutrients, you probably don’t need to worry about adding more boron. Boron deficiencies are generally more likely to appear when a grower is using heavily filtered or reverse osmisis (RO) water to feed plants, since boron is found in most tap water, but that’s actually not the most common reason growers see boron deficiencies in their cannabis plants! As long as you’re giving your plants a good source of nutrients, you probably need to…
2.) Adjust pH to Correct Range
But the reason most growers see boron deficiencies is because boron is best absorbed at lower pH ranges. When the pH gets too high, your plant may exhibit signs of a boron deficiency even if it’s physically there near the roots.
Learn how to manage your pH when growing cannabis.
In soil, boron is best absorbed by the roots in the 6.0 – 6.5 pH range (in soil, it’s generally recommended to keep the pH between 6.0 – 7.0, but boron specifically tends to be best absorbed below 6.5).
In hydro, boron is best absorbed by the roots in the 5.5 – 6.2 pH range (in hydro, it’s generally recommended to keep the pH between 5.5 – 6.5, but boron specifically tends to be best absorbed below 6.2).
3.) Give Plants Enough Moisture
Boron is not absorbed well if there isn’t enough moisture, for example if plant is underwatered or humidity is very low (below 25% relative humidity in the air). Proper watering practices will help prevent underwatering, and a humidifier may be needed to achieve the best growth if your grow room is very dry.
4.) Watch Leaves for Recovery
If you suspect your growing cannabis plant has a boron deficiency, flush your system with clean, pH’d water that contains a regular dose of cannabis-friendly nutrients. Old damaged growth will likely not recover. Watch plant over next few days to make sure that the problem stops spreading to new growththat the problem stops spreading to new growth

Thanks for the response, but the Boron def isn't purple.

Yeah it sure is a strange one, i've looked a hundreds of pics of sick plants and that was the closest i could find to yours, there has to be an explanation, hopefully sooner than later, goodluck.

Phosperous deffiency can cause purpling of leaves and stems.
Maybe you can try and give them some bonemeal and/or batguano.

https://hightimes.com/grow/grow-qa-stems-and-leaves-turning-purple/

At this stage I'd try flushing them thoroughly w/water and feed with any popular nutrient in other words a "known quantity" rather than trying to guess the deficiency.

The purple may not be related if the plants purple up normally.

These never turn purple.

This is also stunted/Gnarly growth, and buds wont form, and eventuall dies. SOMETIES they do come out of it a little, but never more than 15% recovery.

My buddies are doing it on no less than 7 strains

NDNguy/Nevils SEED BANK 88 G13 x Hashplant
THSeeds.. The Hog
Mr Nice SSH x Shit
Mr Nice SSH
Coastal Seeds Puck Yeah
Bodhi. Mt Gogi
Swami Organic Seeds Blue Orca x 85 RKS/Uruapan
Dr Atomic Atomic Lights
Bros Grimm C99.

They NEVER DO THIS INSIDE.

It must be a bug of some sort.

No Bugs. Some plants right next to the others are fine.

I also feel like this is is phosphorus during flower deficiency.
https://www.alchimiaweb.com/blogen/deficiency-excess-phosphorus-cannabis-plants/
The picture at https://hightimes.com/grow/grow-qa-stems-and-leaves-turning-purple/ looks very much like your opening photo as well.

It seems like you are feeding with plenty of P, so all I can think is lockout is occuring from excess of another nutrient or a PH problem.

• Delayed growth of the smallest leaves
• The stems, petioles, and other parts of the plant turn purple
• The most affected leaves become necrotic, turning purple or bronze, drying up and wrinkling and finally falling down from the plant
• Buds are smaller and don’t develop as they should
• Plants are more susceptible to any type of pest or disease caused by fungi, insects, viruses…

I'd say to much moisture is getting those leaves. Need more photos; looks kind of thick and bushy in that garden? More info on outdoor conditions would also be helpful? Plenty of times during day plants leaves can get wet without it raining. When are the leaves wet/moist? Thin a plant or two out and see if the problem clears up, is where I would start.

Check individual branches or stems that are affected for anything abnormal looking; photo's of said affected branches and stems could be helpful.

I'll third the phosphorus deficiency.

I just went through something similar at the end of flower with my last go round. I think mine was caused by too much magnesium by overuse of cal/mag and epsom salts. Plants that don't turn purple turned very purple, and the buds never really put on weight.

Excuse me if I’m incorrect about this but you haven’t shared the ph of the soil have you?

Do you know the ph?

PH is 6.2

Personally I would start by uppin the ph, adding something like one tbsp per gal lime

Yea if your plant doesn’t like the ph then you’re going to have deficiencies everyday and you aren’t going to be able to tell a distinct proble. Just a whole bunch of problems

6.2 is too low for my comfort level. If it were 6.0 or 6.1 it would 100% be the problem imo, so 6.2 is just too low for my liking

bacteria or fungal infection….it's in the soil, rampant in my area for 5-8 years now.

a soil test will help you figure out if there is a deficiency or lockout from nutrient imbalance.


by chance are the indoor and outdoor soils identical?


in beds/bags or ground?


using any kind of spray to control pests?


inquiring minds want to know...

Indoor/Outdoor soil is the same

Promix BX.

7-20 gallon Smart Pots. Both in, and out.

Im also trying to help out another guy, on another forum, who is also having the problem, and whose photo I posted.

Ive never had that problem inside, and only started seeing this the last 4-5 years.

My friend in my town is also having the same problem. Im investigating.

Never seen it since 1972.