Spot Sulfur Deficiency in your Cannabis Plants Right Now!

When you are looking at your cannabis plant and you notice that your top leaves are turning a lime green color.

This could be a sure sign that you might have a sulfur deficiency going on.

The young leaf will start to have yellowing between the veins eventually then turning to yellow.

It shows in younger leaves first then older leaves.

Just by looking at the older leaves on the bottom of the marijuana plant you’ll notice yellowing start to occur.

When your plants are lacking sulfur it can be all so confused with a nitrogen deficiency.

If you think your marijuana plants are lacking sulfur check out some of the signs below to be sure. 

Signs of sulfur deficiency

Here are some of the signs of a sulfur deficiency with your cannabis plants.

  • New leaves turn lime green to yellow
  • Stunted growth
  • Leaf veins will eventually turn yellow
  • Leaf tips can appear burnt
  • Long purple streaks on stalk
  • Leaf tips may hook downward
  • Leaf color is pale
  • Stalk turns woody
  • Small bud development
  • Start opposite the tips of the leaf

Why is sulfur important to cannabis?

Sulfur is responsible for the building of essential amino acids for the plant.

Cannabis does not require high amounts but is a crucial part of the puzzle.

One thing about sulfur is that it acts like a PH buffer not only for plants but also for water.

Sulfur is involved in the formation of oils and flavors of the cannabis plant it works with other micro-nutrients. 


Causes of Sulfur Deficiency

Here are some of the causes of sulfur deficiency in cannabis:

  • Over watering, when growing in soil
  • Soil PH is high above 6.5 (check your soil PH values)
  • High PH in Hydro setup
  • Growing outdoors, lacking sulfur in the soil.

You can also run into Sulfur Lockout.

Sulfur Lockout happens when the PH is above a certain level causing the medium to become Alkaline for the roots.

This stop’s the uptake of sulfur by your cannabis plants.

Here are some PH values to watch for if they are above these values:

When growing in soil: PH levels of 6.5 or higher

Hydro and Soil-less Mediums: PH levels of 6.5 or higher    

How to Fix Sulfur Deficiency

The best ways to fix sulfur deficiency with marijuana is:


Growing in soil dry out plants first. But not bone dry


Flush your plants with PH balanced water.


Adjust the PH level in soil.


Correct the PH level in water/ nutrients.

The optimal values should be in the following range:

Soil, 6.0 – 6.5 pH range. Hydro or coco coir, 5.5 – 6.2 pH range


Epsom salts have been used to increase the levels of sulfur in your row medium by adding 1/4 to 2 teaspoons per gallon when required.


Potassium sulfate can also increase sulfur levels.


Magnesium sulfate could be added just watch if you use cal/mag.


Outdoor grows can try a mushroom compost and not the magic ones!


If you grow outdoors, you could add manure, but I don’t smoke shit.

Signs of excessive amounts of sulfur

  • Leafs turn brown , with dark spots
  • Blocks the absorption of other nutrients such as phosphorus.
  • Grow medium becomes acidic, lower than PH 5

How to correct excess sulfur

It is very rare you will have a significant amount of sulfur but can happen.

You’ll notice your plant growth is small all over you have dark green foliage.

Your Leaf tips me also have some burn or color to them.

The best way to treat excessive amounts of sulfur in your cannabis plants is by doing the following.


Dry your plants out first.


Flush your plants. With just water.

Your plants will usually recover .


Correct Ph of soil

Final thoughts


Yellowing between the veins

A sulfur deficiency in cannabis plants can happen. Always make a note to check the top of your plants.

Look at new leaf growth to see if there is any strange growth or discoloration of the leaves.

If you do notice this before it becomes an issue you can try supplementing with some Epsom salt or even magnesium or potassium sulfate if you so desire.

It all boils down to having a great PH level in general with all of your marijuana plants.

It’s always good to check the PH of the soil or your grow medium at different times of the grow.

Have you had a sulfur deficiency in your plants?

How did you recover?

Let me know in the comments.

Keep Growing my friends.

image credits: Image

2 thoughts on “Spot Sulfur Deficiency in your Cannabis Plants Right Now!”

    • It is 1/4 – 2 teaspoons of epsom salt . I always start out low and work way up if needed. Thanks for noticing it I typed it in wrong.


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