Manganese Deficiency In Marijuana Plants

November 4, 2020

Manganese is vital for disintegrating enzymes, creating chlorophyll and as part of the photosynthesis process. It also makes sure nitrates can be used for creating proteins, very important for marijuana plants. Manganese deficiency in weed plants is quite infrequent and usually has something to do with a lack of zinc and iron. Read this article and learn how to recognize and fix a manganese deficiency in your marijuana plants.

Signs of a Manganese Deficiency

Signs of manganese deficiency in marijuana plant
Signs of manganese deficiency

Usually, the veins on the leaf stay green. The outside part of the leaf turns a dark green color. If the plant has too much manganese, it will cause a lack of iron. Manganese is fixed and doesn’t travel throughout the plant.

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The leaves could turn yellow between the veins, having speckles of brown spots on the damaged leaves. It is possible for the lifeless brown spots to expand and destroy the entire leaf. Another thing – the leaves could fragment and disintegrate.

Manganese deficiency will stop the growth of your plant. It starts to become yellow at the bottom of the leaf, then spread more noticeably, getting closer to the tips. Not sure if your plants have a manganese deficiency? Read the article Nutrient deficiencies in marijuana plants for a list with pictures of all deficiencies.

How to Fix a Manganese Deficiency

If your plant lacks manganese and you are in desperate need of help, try foliar feeding your plant with a fertilizer that is highly soluble in water and has plenty of manganese in it. The fertilizer you choose can be a hydro micro, a unique Fe-Zn-Mn fertilizer, or also a manganese chelate.

You can simply add the fertilizer to your water nutrient solution. You can try compost and greensand, as they are high in manganese, but their consumption rate is less. Marijuana Booster is a great product to use if you want to make sure you have a good mixture of all nutrients.

Maximize your grow by giving your plants the nutrients they need from seed to bud. Grab our complete fertilizer set now.

List of Marijuana Plant Symptoms

Leaf Color: 

  • Pale Color Leaves
  • New Leaves Turning Yellow
  • Lower and Older Leaves Yellowing
  • Yellowing Between Veins
  • Veins of Leaves Stay Green
  • Brown or Dark Spots
  • Speckling / Patchy Pattern

Leaf Symptoms: 

  • Top Leaves / Newer Growth Damaged
  • Lower Leaves / Older Growth Damaged
  • Yellowing Between Veins
  • Veins of Leaves Stay Green
  • Spots
  • Speckled / Patchy
  • Less Growth
  • Unusual Growth

Plant Symptoms: 

  • Slow Growth

Prevent deficiencies

Prevent manganese deficiency
Prevent manganese deficiency

If the pH is too high, or your plant has an overabundance of iron, it may start showing evidence that it is lacking manganese.

Now keep in mind, once you get rid of manganese deficiency, it could take up to one week before the issue is no longer spreading. Any leaves that were harmed because of the deficiency mostly likely will never bounce back, so instead look at the other parts of the plant to determine that it is getting better.

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When growing marijuana in soil the roots will consume manganese far better in the pH ratio of 6.0 – 7.0. Although there are growers who prefer having the pH set more in the 6.0 – 6.5 range when you think you have a manganese deficiency.

If you are hydro growing, the roots will consume manganese much better somewhere in the 5.5 – 5.8 pH ratios. Usually when hydro growing it is better to have the pH set around 5.5 – 6.5, but manganese does consume better at 5.8.

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If you ever think your marijuana plant is lacking manganese, go ahead and fill your system with pure, pH water that has a normal amount of the necessary nutrients for marijuana (which should contain manganese). Doing this gets rid of additional iron and salts that could be blocking the absorption of manganese. It also brings the pH levels where they need to be while giving your plant nutrients it was lacking.

You want to stay away from high pH ranges which easily cause your plant to lack the proper amount of manganese. If for any reason you can’t resolve your deficiency issue, check out our support page for more help.

It takes practice and learning to become a grow expert. Learn how to grow marijuana like a pro in my blog.

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Happy Growing!


FAQ About Manganese Deficiency

What causes manganese deficiency?

Insufficient manganese in weed plants usually has something to do with a lack of other nutrients like zinc and iron.

What are the symptoms of manganese deficiency?

Among the most common signs are leaves turning yellow and noticeable small and brown malignant spots in the center of marijuana leaves.

How to fix manganese deficiency in plants?

One good way to fix a manganese problem is by foliar feeding your plant. Use it with a fertilizer that is highly water-soluble and contains sufficient manganese content.

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 Az okos másén, a hülye pedig… – Tanulságok! – Oldal 6 – Kender Fórum ,06 Feb 2014
    […] hiány: Marijuana nutrient deficiency - Manganese - TÖRÖLJÉTEK MINDEN HOZZÁSZÓLÁSOMAT! Válaszol […]
  2. By Jesse ,31 Oct 2014
    I've been having a hell of a time with my nutes since I started my 2 months ago. I'm hoping someone on here might have some helpful info. I'm using coco with a flood and drain table. I went heavy […]Read More
    1. By peter f kovak ,31 Aug 2018
      I gave my plants to much miracle grow they are starting to wilt what can I due
  3. By Sweet Baby Ray ,25 Feb 2015
    Can I use your booster nutrients in conjunction with Canna hydroponic nutrients?
  4. By Faceless ,15 Jun 2015
    Have you checked your oh? Ph is always first priority even before nutrients. Having the proper ph when you flush is essential to helping the recover from lockout.
  5. By Richard ,15 Jun 2015
    Question... I have a plant that was vegging for first two months, than for a month I budded , now it's vegging again.. Should I get rid of it or let it keep growing. Thank you
  6. By Symptom Checker – Identify Marijuana Plant Problems ,20 Jul 2015
    […] Manganese deficiency […]
    1. By Sean ,27 Apr 2020
      I am using calmag and wondering how long to wait to see if it is working?i have a magnesium deficiency
  7. By Stop Zinc Deficiencies In Marijuana Plants Now! ,03 Aug 2015
    […] deficiencies are similar to manganese and iron deficiencies, accept that they influence new growth, causing them to become motionless. […]
  8. By What Do Marijuana Plants Need? ,23 Oct 2015
    […] especially when compare to the macronutrients. Micronutrients include zinc, copper, iron, boron, manganese, and molybdenum. A good option is the Marijuana Booster. A great product composed of the exact […]
  9. By joe boi ,27 Jan 2016
    New to ge Rowning this type of croup any advice on starting had good results withblac magic worm casing worm po lol gonna try nails for iron? A good top soil? Whats a good soilmix to start with? Findmyself peoblestart […]Read More
    1. By Mamma Luca ,06 Apr 2017
      Say what? what language do you speak fluently...use spell check friend... to grow is to communicate your needs clearly, then the wealth of information ... cause you have questions will flow, like the weed you want to grow.... Cheers.
  10. By latewood.ILGM ,03 Feb 2016
    joe b oio, I had a hard time understanding exactly what you are asking. I believe that you would be best served by joining our Support Forum, where we have many experts and knowledgeable members will to guide you. Peace, […]Read More
  11. By Micro Nutrients For Marijuana Plants ,28 Oct 2016
    […] Manganese (or ‘’Mn’’, atomic number- 25 and atomic mass of approximately 55) is responsible for the production of enzymes and chlorophyll production vital for the photosynthesis. Its deficiency has various results which depend on the species. Cannabis plants’ chloroplasts […]Read More
  12. By Tumblecreekkid ,23 Jun 2017
    Have Amnesia Haze Autoflower, started over sixty days ago .Now shows signs of flowering .I am getting Tiger Bloom by Fox Farms .Is this the best product for this time in my grow cycle ?
    1. By latewood.ILGM ,11 Jul 2017
      Tumblecreekkid, I am sorry mu friend. I cannot say that that is you r best option as tiger bloom is only 1 of 2-3 parts of the Fosfarm Trio system, used in the flowering stage. Join our friendly forum and […]Read More
  13. By Nick ,15 Nov 2019
    Thank you so much really i can't thank you enough✌
  14. By Robbie ,03 Jul 2020
    I had to hold 2 Budda Kush in Veg for four months because there was no room . Anyways the 2 plant did good but I never got any smell even flowering no smell but frosty buds all over . […]Read More
  15. By Kent ,07 Nov 2020
    Good diagnostic pictures and problem solving tips. I am a first time closet grower and had yellowing of some leaves. Turns out to be manganese deficiency.

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