Have you invested in high-quality marijuana seeds from us at SeedSupreme? Did you follow all the growing instructions you researched before starting your cannabis cultivation journey? 


Despite all this, are your plants still not thriving as they should be? Yellowing, curling leaves and oddly-shaped shrubs may signify potassium deficiency in your cannabis


Don’t despair! 


The good news is that we can solve this problem with a little know-how and some extra effort. Let’s begin.


How to identify a potassium deficiency

There are several signs your plants show if they suffer from this ailment. Some may be confused with other issues, such as nute burn. Check your entire shrub carefully before you decide on a diagnosis.


Potassium Deficiency in Weed


In lower and middle leaves

The signs of cannabis potassium deficiency begin in the plant’s older leaves. These features are very obvious.


The most common problem is a change in the appearance of the foliage. The edges appear crispy and burnt. After burning, you’ll notice that the tips curl. Leaf margins turn pale yellow with dark brown spots while the veins remain the same green color.


In upper leaves and shoots

As the deficiency advances, its indicators move through the remainder of the plant. The growth of your shrubs appears stunted, and new leaves are small. 


There’ll be an increase in space between branches, making the plant appear “stretched.” Another result of potassium deficiency in cannabis plants is that the stem becomes weak and brittle. 


How does the lack of potassium affect the buds?

The most important parts of the plant are also affected by this shortage. 


The blooms are thin and underdeveloped if your cannabis is in the flowering stage.


The formation of buds is slow, causing their size and weight to decrease.


Potassium Deficiency in Weed


Potassium deficiency symptoms

At first, potassium deficiency in weed plants produces only visual clues. 


Once the tell-tale brown spots have appeared in the center of your leaves, you must take action to prevent them from spreading. If not treated in time, the symptoms suffered by your plant will progress.


Evolution of potassium deficiency

Changes to the surfaces of the leaves can continue until most of them are a different color. Ultimately, this results in them dropping off.


The shortage of available foliage to perform photosynthesis can decline the plant’s overall health. 


Blooming diminishes, with some shrubs unable to produce any buds at all. Thanks to a potassium deficiency in your cannabis, stems become skinny and branched.


At this point, your plant has little immunity against pests and diseases, and growth slows down.


These factors culminate in the worst symptom imaginable for any grower: a low yield. You can see why it’s so important for all growers to be able to identify and fix this issue.


What does cannabis use potassium for?

Plants require a wide range of nutrients to grow and reproduce. Potassium, nitrogen, and phosphorus are three important elements that marijuana needs in large quantities.


No matter your shrub’s life phase, potassium is always necessary. It has the same function in both the vegetative and flowering stages.


Several basic tasks will be affected if there’s a potassium deficiency in the cannabis you’re growing.


Potassium in the vegetative and flowering stages

The first task is maintaining the correct amount of H2O inside the marijuana shrub. Potassium is crucial in encouraging plants to move water up from their roots. Adequate levels ensure that the marijuana stems remain upright and prevent wilting.


Potassium is also critical in photosynthesis. It controls the opening and closing of the stomata. These tiny pores in the leaves allow CO2 to flow in and out. A potassium deficiency in your weed means your plant can’t “breathe.”  


Potassium is a key nutrient needed for growth. It activates the proteins responsible for building the leaves and stems and increases your cannabis plant's resistance to pests.


Potassium Deficiency in Weed


Causes of potassium deficiency

Once you’re certain that your shrub is suffering from a potassium deficiency, you should follow a few steps to save it.


It’s important to note that you won’t be able to reverse the color change already present on your leaves. You must take action to prevent further deterioration from cannabis potassium deficiency and protect your harvest.


The obvious question is, are you feeding your cannabis high-quality fertilizers? A lack of nutrients in the soil is the most common cause of deficiencies.


When trying to make up for lack of food, be careful not to go too far and overfeed. Giving plants more nutrients than they need causes potassium toxicity in cannabis


Oversupplying nutrients blocks the absorption of other important vitamins and results in very similar leaf conditions to when there’s a shortage. Nute burn is almost indistinguishable from potassium deficiency. 


If you’re sure that you’ve been giving your cannabis adequate food, there are several other aspects to check in your grow setup.


Suppose you want to know how to fix potassium deficiency in hydroponics? When growing your plants this way, nutrient shortages are very rare. It’s more likely that there’s a problem within your system.




One of the possible causes of plant potassium deficiency is stress.


Marijuana can become distressed if it undergoes any sudden changes. These include under or overwatering, a rapid temperature fluctuation, or a drastic variation in lighting. 


Transplanting your cannabis into a new pot could also be the root cause of the anxiety your plant is experiencing.


How to fix it

Should stress cause the potassium deficiency in your weed, there’s a simple solution.


Leave your plant to adjust to its new living conditions for about four to six weeks. Don’t make any more changes to the growing environment, and water it with care.


It’s very likely that once the plant has acclimatized to its new surroundings, it’ll stop producing the signs of a cannabis potassium deficiency.  


pH variation


Throughout the entire life of your marijuana, it’s essential to maintain a neutral pH range of 6.0 to 7.0 in your growing medium. The soil’s acidity level affects both nutrient and water uptake and could cause your shrub’s deficiency.


Potassium Deficiency in Weed


If you’re struggling to find the cause of the yellowing leaves on your cannabis, check the pH. Measure the acidity of the substrate and the water you use to hydrate your plant.


Are you still uncertain whether you’re dealing with nute burn or a potassium deficiency in your weed? Checking the pH of your soil is a sure way to figure it out. If it’s not within the desired level, you’re dealing with a shortage.


How to fix it

If your plant’s pH level isn’t within the optimum range, there’s a fast fix to get its growth back on track.


Flush your cannabis with neutral pH water, and then leave it to recover for a few weeks. Once the leaves have stabilized, begin feeding with a high-standard fertilizer.


Following this step should eliminate the marijuana potassium deficiency and encourage healthy new buds to bloom. 


Excess salts

Have you noticed that the surface of your soil looks white? Has it even progressed so far that the pale powder has turned into crystals? 


Excessive salts in your growing medium may cause a potassium deficiency.


As the soil becomes more saline, your cannabis plants can’t take up as many nutrients as they need. If you leave the problem for too long, it may reach a stage where food leaves the roots.


Don’t fret. There are a few easy solutions to solve this issue, too.


How to fix it

If you think that a salt surplus is causing the potassium deficiency in your weed, start by improving the drainage of your soil. Work in compost or manure to change the consistency, creating more air pockets for water to flow through.


Another way to correct excessive minerals in your growing medium is to apply mulch to the top. An extra layer surrounding the plant prevents evaporation. The additional water in the soil dissolves any unneeded salts.