Manganese deficiency in marijuana plants

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.

Knowing the signs of manganese deficiency

When new leaves begin turning yellow and show small, brown colored malignant spots in the center of the leaf, this is a sign of manganese deficiency.

Usually, the veins on the leaf stay green. The outside part of the leaf turns a dark green color.

Signs of manganese deficiency

If the plant has too much manganese, it will cause a lack of iron. Manganese is fixed and doesn’t travel throughout the plant.

The leaves could turn yellow between the veins, having speckles of brown spots on the damaged leaves.

Download my free Grow Bible for more tips and read it while you grow your own marijuana.

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.

Fix manganese deficiency

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.
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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

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.

Prevent manganese deficiency

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.

Start with buying the best seeds and fertilizers to guarantee best results! Using the correct nutrients and plant protector will get you a long way and your plants will have less chance of getting sick, in addition of being less vulnerable for pests and diseases. I have created multiple grow sets which features all you need in order to grow healthy plants from seed to harvest!

buy all-in-one marijuana grow set

Buy your grow set

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.

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.

Manganese deficiency in a marijuana plant

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.

Know the best time to reap the fruits of your labor with our free Harvest Guide.

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.

What’s your favorite strain to grow? Please leave comments or questions below and don’t forget to download my free grow bible.

Happy Growing!


Avatar for Robert Bergman

Mr Robert Bergman PhD


Robert Bergman is an Amsterdam-based marijuana grow expert who has years of experience from small grows to massive operations ... See profile

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20 comments on “Manganese deficiency in marijuana plants”

  1. 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.

  2. 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 . Can you tell me what is going on thanks

  3. I am using calmag and wondering how long to wait to see if it is working?i have a magnesium deficiency

  4. 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 learn what you need to be successful.

    We have a mature knowledgeable membership. We are a happy forum. 🙂

  5. 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 ?

  6. 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.

  7. […] 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 become yellow and the stems are still quite green. On the surface of some leaves there may appear spots of white or grey. It also causes Iron- deficiency with similar symptoms to it. […]

  8. 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, lw

  9. 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 with?

  10. 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

  11. 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.

  12. 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 with the nutes and locked them up but I did a good flush and stayed over with a new mixture but ever since then they just won’t grow. Like I said, 2 months and the tallest one is 6″. They are very pale green/yellowish and are now all of them are staying to get dead tips on the end of the leaves. I’ve done extensive research and can’t pinpoint the issue. Does anyone have any suggestions for me?