Potassium in Aquaponics (4 of 4) – Managing Potassium
Dr. Nate Storey: All right, this is Nate Storey
with Bright Agrotech and this is Part 4 of our series on potassium. Now I’m going to
talk about how we treat potassium deficiencies and how we manage our systems so that we don’t
end up with potassium deficiencies really regularly because those can really cut into
our productivity. Historically we have had to supplement systems
with potassium whether it’s a potassium carbonate or a potassium-based hydroxide, we’re adding
potassium to the system. Many folks who are adding seaweed extracts, that kind of thing,
they don’t realize they are also supplementing potassium. We use seaweed extract in our system,
it’s got a rating of 0-0-10, this is our NPK rating, the kelp meal concentrate that we
use has this rating. You can see then that kelp and kelp meal is very, very high in potassium.
Carbonates and hydroxides are also high in potassium and the nice thing is that this
is not supplementing nitrogen or potassium so we end up when we put … Sorry, phosphorus
… When we put a potassium hydroxide, like caustic lye, caustic lye is a potassium hydroxide
… KOH, this is caustic lye, and this is something that we’ll use when the pH is very
low. We also have potassium carbonates, so this
is K, usually it’s like a 2CO3, there’s a few different carbonates there, and bicarbonates,
but we’re adding carbonates and we’re adding hydroxides but they only work at low pHs because
both of these substances, our carbonates and our hydroxides will raise our pH. These are
very, very basic compounds. This is one reason why a lot of people will use kelp to supplement
potassium in their system because it’s pH neutral.
There are a lot of other substances that you can use and depending on how your system runs
you can choose from a number of different things, so I’m going to talk about those today.
So far we’ve just talked about mostly substances that we add to the solution. Now you can’t
spray something like kelp meal concentrate on the plant leaves so you can’t apply it
foliarly which means that the plants absorb it directly through their leaves and can utilize
it. By and large most people were adding their concentrates or their kelp meal concentrates
to the water itself, which is easy but not always the most efficient method.
There are a few other things that we can also do this with, we use potassium sulfate. We
use potassium sulfate here on occasion, and most potassium sulfate has the rating 0-0-50.
This is a very fast response, super fast response potassium addition for systems and if you’re
experiencing potassium deficiency and you want to treat it in the solution I would highly
recommend using potassium sulfate because you get very quick results. Now you can’t
really apply this foliarly, that’s one drawback, you don’t want to be spraying potassium sulfate
on your leaves but it works to correct these deficiencies fairly fast in solution.
Now, if you’re seeing deficiency symptoms and you need to treat it right, right away,
we’re talking about like in the next one to two weeks, then you’re going to have to use
potassium chloride. Potassium chloride, it’s a simple salt, a lot of people people use
it in de-icer, so a lot of de-icing salts use potassium chloride. It’s a great, great
thing to use for foliar applications. Make sure that you check out the Vertical
Food Blog, I’ll talk about how to dose potassium chloride, but I usually recommend somewhere
around like 1/8 of a teaspoon, a very small amount for each gallon of water that you’re
going to apply foliarly. I want to make this clear, you apply this foliarly. Not in solution,
we don’t want to be adding this to our solution. This is a really great way to get a super
fast response out of your plants if you start to see a potassium deficiency begin to develop.
These are a few different options you have for treating potassium deficiencies in your
system. Before you do any treatment, please, please, please read the Vertical Food Blog,
blogs on this subject, they’re going to talk in enough detail that you can make the right
decision regarding which one is the best to use and how much to dose it with. None of
these things are going to destroy your system if you add them.
The big thing with foliar applications of anything is that you can burn your plants
if you apply it at the wrong rate, so it’s always important to know what rates you’re
applying, what substances you’re using and make sure that you’re applying them at appropriate
rates to address the need of your system, so please, please, please do read the Vertical
Food Blog posts on this subject. I’m going to go into a lot of detail for you there and
I don’t want you to go out and just dump a whole bunch of potassium sulfate in your system
and see something crazy happen because you didn’t know what you’re doing. Please do check
out the blog and I’m going to go into as much detail as possible to make this really easy
for you. Thanks for watching this four-part series.
If you find this information valuable and helpful please check out the Vertical Food
Blog and please do check out our products on ZipGrow.com, if you’re thinking about starting
a system. This is Nate Storey with Bright Agrotech, thanks so much for watching.