How to Manage Potassium Deficiency In Aquaponics - Go Green Aquaponics

How to Manage Potassium Deficiency In Aquaponics

Potassium is one of the essential nutrients that plants need to grow. It is one of the three primary macronutrients, along with phosphorus and nitrogen. Potassium can affect the shape, size, and vitality of the plants in your aquaponics system. So if you want to grow healthy plants in your aquaponics system, you need to understand and properly manage the potassium in your system.

In aquaponics, potassium is introduced to the system through the fish feed orsupplements like kelp meal concentrate or potassium hydroxide. However, the potassium levels in the fish feeds are sometimes not enough for the fish and the plants, as most feeds are formulated and made with aquaculture in mind, not aquaponics. So it rarely includes more potassium than what is necessary for the fish. This is why potassium deficiency occurs in an aquaponics system. Potassium deficiency will hurt the plants in the system.


Potassium Deficiency in a Tomato Plant

Why Potassium in Important?

Potassium serves essential functions for plants, and these functions vary on the type of plants and their stage of growth. Up to 80% of the plant's potassium needs are needed early on in their growth. This is because plants rely on potassium to help them open and close their stomata, plants part that is necessary for photosynthesis.

As plant age, potassium is needed to help develop and maintain the function of the phloem, a tissue that moves sugars from the leaves and xylem, a tissue that moves nutrients and water from the roots to the leaves shoots. Without the right level of potassium, plants won't be able to distribute these nutrients properly.

Plants use potassium for growth, help with photosynthesis, and for signaling between cells. Potassium can improve root growth, and make them more resilient to water loss, improve the amount of protein in plants, prevent the spread of certain diseases and make plants more resistant to nematodes.

Plants, especially the flowering and fruiting plants, consume a higher level of potassium. To have healthy plants, you need to higher the level of potassium in your system through supplementation.

How to Identify Potassium Deficiency in Aquaponics Plants

To identify potassium deficiency in your aquaponics plants, start by looking for signs. Plant deficiencies in aquaponics impact the physical appearance of the plants, making it easier to identify what kind of nutrient deficiency is happening in your system.

Signs of Potassium Deficiency:

  • Potassium deficiency results in the very stunted and weak root growth of the plant.
  • The older lower leaves of the plants look wilted, with browning and curling at the leaf edges and yellowing between leaf veins and around leaf edges. If left untreated, the older leaves will begin to die off, but the sign will progress to the upper younger leaves.
  • Browning or burnt look at the leafs' edges.
  • Curling or cupping of leaves.
  • Spotting or rotting of leaves in brown, black or purplish spots


Sign of Potassium Deficiency Leaves with Potassium Deficiency


How to Correct Potassium Deficiency in Aquaponics

Correcting your system's potassium deficiency can be easily manageable if you act quickly. Failure to restore the potassium levels can cause plant growth delay or death of the plants that could ruin your harvest. One of the best steps you can do to manage the deficiency is by adding potassium to the system, balancing the nutrients and pH levels.

Balancing nutrients in the system is very important because some other important nutrients like calcium, magnesium, and nitrogen can result in a potassium deficiency in aquaponics plants even if you are supplementing with potassium. Balancing will also ensure that your plants get the proper level of nutrients they need or risk other nutrients in hindering the plants' ability to absorb potassium.

Another important thing to take a look at is pH balance. pH imbalance will block nutrient uptake through the plant's roots. So it is essential to check the pH to keep the level within the right range and monitor your system’s water quality. If the pH level is not in the correct range, the supplement nutrients may not be able to reach the plants because deficiencies are compounded by acidic conditions and excess calcium and magnesium.

Adding Potassium to Your Aquaponics System

There are several ways to add potassium to your aquaponics system.

  1. Potassium supplements can be introduced to the system by adding the nutrients directly to the water. This is the most direct way of getting potassium to your plants. You can add potassium to your aquaponics system using potassium hydroxide, kelp meal concentrate, or potassium sulfate.
  2. Another way to add a potassium supplement is by applying through a foliar spray on the plant leaves using potassium chloride.

How to Prevent Potassium Deficiency in Aquaponics 

Once potassium treatment is successful, you must take steps to prevent nutrient deficiencies in the future. Here is how you can avoid potassium deficiency in your aquaponics system.

  1. Check your system's nutrient level regularly and supplementing the needed nutrients will help you maintain the balance of your system. 
  2. Using a high potassium fish feed will also help maintain the potassium level. 
  3. Keeping a potassium supplement in hand is also a great idea to supplement as soon as needed.
  4. Monitor the condition of your plants' leaves for signs of nutrient deficiency. 
  5. Test the pH level of your water regularly. 


When it comes to managing and preventing nutrient deficiency in your aquaponics system, the best thing you can do is proactively solve the problem instead of waiting for the problem. You can create a supplementation calendar to monitor your system and to avoid nutrient deficiencies like potassium. Remember, your aquaponics system's success is always in the proper monitoring and balance of the whole system. Thank you for reading this article. Read our blog, the ultimate aquaponics beginner' guide.


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