Given that you are growing plants in an aquaponics system you will probably be asking yourself how you can add potassium to the system and get it in a form that the plants can utilize without disrupting any of the other balances.
Today we will be considering this question, and walking you through the appropriate steps to help you succeed.
Potassium is a vital part of plant growth, so when a deficiency occurs, it is important to act quickly.
You can add potassium to your aquaponics system with a foliar spray on the leaves, or by adding supplements to the water that are being cycled through your aquaponics system. Both are acceptable methods, so let’s look at the merits of each approach.
Why Do I Need to Add Potassium?
There are three primary nutrients that plants need in order to grow:
- phosphorus
- nitrogen
- potassium
If you are short of potassium you will find that any plants in your aquaponics system will be in bad shape and often weak or dead, depending on how much deficiency you have.
So that means you need to control the potassium level in your aquaponics system and sometimes you will need to add potassium.
Potassium deficiencies in aquaponics are very common because many of the potassium supplements on the market are for fish and not for plants.
They usually do not contain the right amounts to correct the balance and raise potassium levels to the correct level and as a result your plants can become sick.
The Importance of Potassium in Aquaponics
Potassium is especially important for younger plants, and up to 80% of their potassium requirements will be utilized during early stages of growth.
Without potassium, plants cannot open or close their stomata and will not be able to photosynthesize.
Potassium also assists younger plants in developing stronger root systems, gathering proteins, and resisting diseases and nematodes.
In their later stages in the plant’s life cycle, potassium is important to facilitate the development of phloem and xylem. Phloem is the tissue that moves sugar from the leaves and xylem moves nutrients and water into the leaves.
Potassium is also important in transporting other nutrients to their targeted areas; without the potassium, the plant will have a hard time moving nutrients to where they are needed.
Plants that fruit and flower (which you are likely growing in aquaponics) are particularly sensitive to potassium deficiencies, and don’t overlook this issue, or you might not have a viable harvest from your aquaponic garden.
How Do I Know If Potassium Is Needed?
When a plant is deficient in potassium, typically you will see curling leaves, yellowing leaves, yellow spots on the leaves, or brown edges to the leaves.
As the potassium deficiency progresses, the plant will lose older leaves, and younger leaves may appear dior like they are wilting or sick.
The development of the plant’s roots will also show signs that the plant is potassium-deficient. Its root development will be weak and stunted at this stage.
On the whole, when you see one or more of these potassium deficiency symptoms, you need to act quickly as every day will not only set the plant back further, but also plants that soil back further, and also the plant will be further reduced in it’s ability to recover once you have added potassium.
You may be asking yourself, how do I add potassium to aquaponics? We can determine that next.
Method One: Foliar Spray
If you prefer not to directly supplement potassium to your aquaponics system, the easiest method might be to use a foliar spray of potassium chloride.
Pretty straightforward. You simply create a foliar spray out of potassium chloride and then spray the potassium chloride solution on to the plants, coating the leaves about once a week.
This solution circumvents some of the difficulties you can have when using potassium directly in your aquaponics system, which we will cover in the next section, and can be potentially more effective with your system, in general, in returning potassium back to the plants.
The downside is that utilizing a foliar spray requires multiple labor intensive applications to the leaves of your plants; rather than simply adding an additive to your system and letting the aquaponic system evenly distribute it through your plants.
You could, if you wished, simply buy a foliar spray commercially. You can find these online, and they are readily available.
Just buy a foliar spray, fill your spray bottle and apply according to the instructions. Nothing special to set up. Just apply as directed.
From Experience: the sponsors of the sprays may require different frequency and concentrations. Again, so check the instruction on the bottle or package.
Method Two: Supplement In The Water
Typically, in an aquaponics system, you try to add the nutrients to the water for the plants to uptake through their roots.
After all, they are behaving like they would in nature and it is usually the easiest thing to do.
We will talk about how to do it, and discuss the issues you may run into.
For potassium, you will want to purchase a supplement that can be used in the aquaponics system. This might be potassium sulfate, potassium hydroxide, and possibly a kelp meal concentrate.
All of these will work to increase the potassium level in the water.
As noted before, potassium is also a fish supplement and therefore it may be a relatively small amount.
Best Practice: After adding any potassium supplement, be sure to check the nutrient level of the water and confirm you have corrected the deficiency.
Issues With Potassium Supplementing
As stated, there are a couple issues you may run into when trying to add potassium to aquaponics.
Potassium can be locked out from plant uptake even when it is present in the system, as other nutrients (typically calcium, nitrogen, and magnesium) can reduce potassium availability.
You will also want to ensure that you are balance these nutrients so they are not contributing to the issues of potassium uptake, or preventing plants from being able to uptake potassium.
You will also need to examine the pH levels, as well, since acidic conditions can also negatively affect the plants ability to uptake potassium.
If the pH levels are not balanced, the plant may struggle to uptake any nutrients at all – so keep in mind to always test the water quality and make note of any imbalances (including pH and then other nutrients).
If you are having a lot of difficulty with all of this, you could always try getting a potassium foliar spray in the meantime so you can give your plants some potassium while addressing those other issues.
Conclusion
Introducing potassium into your aquaponics can be a little complicated, especially if there are other issues that you need to address first.
However, it is worth finding the time to do so or your plants will not grow well, and you will not have a good crop.
Consider a foliar spray if you are having trouble with the potassium or other nutrients. Regardless, you need to get your aquaponics water back healthy and balanced.