Potassium, is the “K” in your N/P/K Ratio. Like Nitrogen and Phosphorous, it is known as a “Macro nutrient”, and is one of the three main elements needed in plant growth. Here will will discuss Potassium Excess, this is when your plant has too much Potassium.
Potassium helps the pores of the plant open and close, which essentially, allows it to sweat and breathe. It is also responsible for the production of many enzymes the plant needs to grow. With out it, the plant would not be able to produce the starches needed for photosynthesis.
Too much potassium can cause the plant to have “lock out”. This will stop the plant from eating other vital elements, and other deficiencies will soon show. If not solved quickly, it can have a lasting effect on your harvest.
If you think your plant is suffering from Potassium Excess, then feel free to ask for help in our cannabis growers forum
The Effects of Potassium Excess.
Because Potassium excess will cause lock out of other nutrients, it can be wrongly diagnosed. Look at out for the top leaves growing thin blades. Middle leaves will develop burn around their tips. Flowering will be slow to start, and flower growth will be diminished.
What Potassium Excess Looks like

How to Fix Potassium Excess
How to fix a potassium excess will depend on the medium you are growing in. It can be as simple as flushing your medium, or, if growing outdoors, you may have to plant crops that will eat a a lot of K. This will make sure whatever is in your soil will be eaten faster.

Potassium Excess in Coco & Hydro
Flushing your medium, with plain, PH’d water, is always a good way to reduce the amount of any nutrient in your medium.
Once you have flushed, or removed your old reservoir, feed your plants again, at half of their usual EC. This will restore their colour, to a healthier shade of green, within a few days. But any damaged or burnt leaves will not fully recover.
If you don’t have an EC meter, and you’re growing in hydro or coco, you will need one! If you would like to know what your plant is eating, you need a good reliable EC meter.
Potassium Excess in Soils
It will be harder to remove any element in soils than it would be in hydro or coco, as the drainage isn’t so good and you can risk over watering your plants. It is best to do one big flush, to remove as much as possible from the medium. After the flush, let the soil dry out until the pot is light before watering again.
Once the medium is dry, continue to water your plants, with just water! They will eat the potassium that is stored in their plant matter. Your plant will lighten up within a few days, to a week, depending on how bad the toxicity is.
Thanks for reading! You can find more information on anything related to growing in our cannabis grow guides. All of our guides are written by experienced growers, and members of our cannabis growers forum. If you have any questions, sign up. It is free, and we are always happy to help!