Why Are My Marijuana Plant Stems Purple?

January 27, 2021

Seeing your marijuana plant with purple stems can be a little scary. You may become quite worried about the overall health of your plant, but this may not be as bad as you think. Below are some things you need to know about cannabis purple stems.

In this article we will discuss:

purple weed stem
Purple stem

If you notice the stem of your seedling or marijuana plant has turned purple and there are no more indications of issues, this means their problem is genetic. There are certain marijuana strains that automatically grow with purple stems, more so when the seedlings are budding, or even once the plants start receiving cooler temperatures during the night.

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Solution for purple stems

If your plant seems to be in good condition aside from the stems being purple, refrain from making any changes for a one or two weeks. The majority of the time the plants will turn green fairly quickly. Provided that your leaves appear to be healthy and there aren’t any of issues you are aware of, most likely the purple stems are nothing to be concerned about.

If your marijuana plant is struggling to grow properly you might want to check out our list of nutrient deficiencies to get ahead of the issue!

If you suspect that your marijuana plant may have a nutrient deficiency, maybe because the plant growth has slowed down or the color of the leaves is fading, then your plant could be magnesium deficient. This can sometimes create purples stems.

purple stems cannabis
Plant with all stems purple

If this is the case, the issue will be resolved with ease by adding more magnesium the next time you water your marijuana plant.

Here are some great magnesium sources for your plants:
– Epsom salt, just add 1 tablespoon per gallon
– Cal-Mag
– A nutrient solution that works well with marijuana has the proper amount of magnesium for your plants

Tip: make sure to download my free Grow Bible for more information about purple stems cannabis


Usually, your purple stem problem is nothing to worry about at all. But to be on the safe side check for any signs of magnesium deficiency. Take a look at our article on identifying magnesium deficiency for more detailed information. If there is no nutrient deficiency, then luckily, purple stem will only last for a short time.

Thanks for reading. Please leave comments or questions below and don’t forget to download my free grow bible


Cannabis Purple Stems FAQ

What Causes Purple Stems

If you notice the stem of your seedling or marijuana plant has turned purple and there are no more indications of issues, this means their problem is genetic.

How Do You Treat Purple Stems

If you suspect that your marijuana plant may have a nutrient deficiency. If this is the case, the issue will be resolved with ease by adding more magnesium the next time you water your marijuana plant.

How do you fix weak stems?

If it’s stretching, add more soil right up to the first set of leaves to strengthen the stem.

The founder of I Love Growing Marijuana, Robert Bergman, is a marijuana growing expert that enjoys sharing his knowledge with the world. He combines years of experience, ranging from small-scale grows to massive operations, with a passion for growing. His articles include tutorials on growing... [read more]

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  1. By rich richter ,20 Sep 2015
    should i remove all the purple stems from the plants. will it hurt the plant to leave them on. thank you rich
  2. By Brian T ,24 Sep 2015
    Thanks for that info about the purple stems which look exactly like the stems in the photo on your page. My plants are only 4 weeks old and Auto flowering, the nutrients I am using do contain Mg so it […]Read More
  3. By latewood ,25 Sep 2015
    Thanks for sharing Big Tom :)
  4. By Rayray ,02 Dec 2015
    My plant is wilted an it was doing great till I switched it from 1 bucket to another b cuz it's to big red my arogarden an I need to knw if it's gonna make it an will it harm […]Read More
  5. By latewood.ILGM ,05 Dec 2015
    Sounds like you lost that one, mate. Start again. Download and read Robert's Free grow bible and learn how to start seeds correctly and keep them thriving.
  6. By Mark ,20 Apr 2016
    Purple pot is one thing. How about other colours I have seen over the years. I have been growing many years. Kind regards, Mark.
  7. By latewood.ILGM ,21 Apr 2016
    Mark, Purple pot :) I think it is more important to yield quality pot before worrying about color. :) Most off colored buds comes from colder temps in flower. I always appreciated what nature provided me, concentrating on a fine […]Read More
  8. By King Spike ,01 Jun 2016
    Hello, first time grower here. My plants are just 2 decent mid grade seeds I got from a friend. The plants are about a month old. I transplanted them into bigger containers with a mix of 10-10-10, good garden dirt […]Read More
  9. By latewood.ILGM ,12 Jun 2016
    King Spike, Sounds like you have a plan; However, Using common dirt from the ground can lead to unwanted pests and possibly could be detrimental to your plant. I advise you to join our support forum. We have many knowledgeable […]Read More
  10. By Robert Gore ,25 Jul 2016
    Where do I go to ask questions
    1. By Roy ILGM ,25 Jul 2016
      Hey Robert, for questions that concern growing the best place is the forum, our experts and fellow growers will help you out there. If you have any questions about our sales/logistics process you can email [email protected] Cheers!
  11. By [email protected] ,09 Sep 2016
    I live in COLORADO most of my STRAINS have the the PURPLE STEMS I believe its GENETICS .I have 4 indoor and 4 outdoor .I use ROOTS707 soil And the FLORA GROW, BLOOM & GRO NUTREINTS . MY LEAFS are […]Read More
  12. By elizabeth ,12 Jun 2017
    Hi (already a pun). I am growing several types of Pot from seed, including the 3 precious seeds i got from my 'Purple Kush', ...all from a medical dispensary. There are 3 of 14 plants exhibiting the purple branches, one, […]Read More
  13. By Chrisman joe ,11 Jul 2017
    My plant is doing fabulous..........😂
  14. By Shaun ,30 Jul 2017
    I leave my lights on 24hrs and stems turn purple that normal
    1. By latewood_ILGM ,05 Aug 2017
      Shaun, No. It is not normal to leave the lights on for 24 hours. Plants need rest, just like humans. ;) Purple stems. Could be too cold an environment or a deficiency. Perhaps you should join our support forum. We […]Read More
  15. By Skp ,16 Nov 2017
    Seedling leaves look crinkled? Any help would be great.
    1. By latewood_ILGM ,21 Nov 2017
      Skip. Go here: support.ilovegrowingmarijuana.com We have a super friendly community. Experienced growers and expert staff will to help you grow successfully from start to finish. It sounds like you placed a seed into hot fertilized soil. Nutrients burn the roots […]Read More
  16. By mark genanatti ,05 Aug 2018
    every grower of cannibus has there different ways of growing great nugs the biggest thsia seed at this time and a little more intense just be patienting is dont ignore your medicine and alot of patience just dont be in […]Read More
  17. By Wonder ,30 Oct 2018
    It's so strange to read that purple stems indicate a lack of magnesium. You must have mistaken it for phosphorus)
  18. By latewood_ILGM ,04 Nov 2018
    Wonder, Thanks for catching that. I will send the edit info to the editor. Again. What was mentioned that I agree with is: The cause of purple in most cases is genetic. Happy growing :)
    1. By Cody ,30 Mar 2021
      Three years later and it hasn't been updated yet, it still says magnesium deficiency in the article.
  19. By Karen ,05 Dec 2018
    I have throfty foamy stuff that is circulating in my hydro why. Plants aren’t doing well
    1. By latewood_ILGM ,06 Dec 2018
      Karen. This is a deficiency article. Please join us at: support.ilovegrowingmarijuana.com where we are set up to help you in a Q and A format which allows you to post pictures. Foam build up in your reservoir is caused by […]Read More
  20. By Larry ,29 Apr 2019
    Everyone says that some strains have purple strpems....but no one lists which strains..... It would be advantageous to provide this information.
    1. By Vaughan ,07 Jul 2020
      Did anyone answer this ? I am curious to this one as well
  21. By Krzysztof Massachusetts ,27 May 2019
    Thanks really helps me allot Im think im need callmag but im not ben sure now im know for sure hehe thsnks again
  22. By Daniel ,17 Jul 2019
    It's not about this article...but I had bug problem..."outside" so what I did was. Lightly Sprinkle some black pepper around the base of the plants and lightly over the leaves...it worked no more bug problem..
  23. By Chris ,13 Oct 2019
    Appreciate the information. :) I was a little worried that my seedlings that just popped out of the soil might already be having some issues. Thank you
  24. By Jarrod ,15 Oct 2019
    Can I grow in straight horse manure cut with last years grow Medium?
  25. By Sid bueno ,04 Nov 2019
    Thank you for the information my outside plants my stem was getting purple from the bottom of the stem looks like from cold temperatures at night Thank you once again
  26. By Joseph ,12 Nov 2019
    I just want to thank you for given me the information that I need I'm learning a lot from you
  27. By Graeme ,24 Feb 2020
    If mag deficiency causes purple stems then wouldnt this mean the plant is defici in magnes???
  28. By Farryl ,26 Aug 2020
    Purple stem yes ,the banana looking object growing on the stem , should I be concerned , male , or hermafidite ,.
  29. By Dale ,27 Aug 2020
    I have 3 gorilla glue clones , one entire plant has all purple stems. The only one , they all get the same feeding.. Very healthy looking plant.

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