Hey.
This is Nate Storey with Bright Agrotech.
Today we're going to talk a little bit about magnesium as part of our ongoing series on
Managing Your Nutrients in Your Aquaponic System.
We've talked about the three primary plant nutrients.
This week we're concentrating on secondary macronutrients.
Magnesium is one of these, and it's really important to the plant, almost as important
as a few of the primary plant nutrients.
Magnesium exists in your system with a positive charge.
You've got magnesium just floating around in your system.
I will say magnesium is one of the "big three."
It interacts really strangely with calcium and with potassium as well.
That's another reason why you should download the deficiency key and learn how to diagnose
magnesium, especially when you learn how to diagnose calcium, and you've learned to diagnose
potassium.
Magnesium is mobile in the plant, which basically means that, as the plant needs magnesium in
the growing parts of the plant, it can scavenge it from older parts of the plant.
Oftentimes when we start to see magnesium deficiency, it shows up in the older leaves.
What it typically looks like is interveinal chlorosis, just generally.
It's a yellowing of the tissues ... They turn yellow, or they turn white ... between the
veins.
It's important to understand what the specific parts of magnesium deficiency look like, because
they can resemble potassium deficiency in some instances, and in some instances, even
calcium deficiency.
One of the reasons that you see chlorosis as part of the magnesium deficiency is because
magnesium is really, really core.
It's integral to photosynthesis.
As the plant begins to lack magnesium, what ends up happening is the chloroplasts end
up breaking down, and the ability of the plant to photosynthesize is really decreased dramatically.
Look for that chlorosis, and look for some of the more specific symptoms.
Use the key to do that, because it can be pretty tricky figuring out what a magnesium
deficiency looks like.
I will tell you that potassium is the most common deficiency in aquaponic systems, and
then calcium and magnesium are second to that, and they're oftentimes interrelated.
Be thinking about that pretty carefully.
If you do think you have a magnesium deficiency, there's a few different ways that you can
treat it.
If your system has a neutral pH, or runs a little bit high, you basically want to use
something that's neutral to treat your magnesium deficiency.
Most commonly this is Epsom salt, cheap, regular, old Epsom salt.
You can get it at the drugstore, at the dollar store, Walmart.
It's really inexpensive, and it's really, really effective as a magnesium supplement.
Epsom salt is a magnesium sulfate.
It's basically magnesium with some sulfate on it ... SO4.
You can add that to your system.
There are varying rates.
I'm not going to give you a dosage right now, because it really depends on what the starting
concentration of magnesium is in your system.
You can add Epsom salt.
You can add, actually, quite a bit of it.
It's not going to harm your system typically.
It's pretty darn benign stuff.
You don't want to just dump a whole box of Epsom salt in your system, but you can certainly
go and add a few ounces for larger systems and continue to treat until you actually see
that magnesium deficiency start to go away.
That's the best way to take care of it in systems where your pH is rather high.
If your system pH is low, then what you want to use is hydrated lime, or agricultural lime.
Agricultural lime is a hydroxide.
It's a mixture between calcium and magnesium hydroxides.
Depending on the lime that you'll get, you'll see it tested at different rates.
Some of it has more magnesium than other types of hydrated lime.
Check the bag; check the rating on it.
In low pH systems a mixture of hydrated lime and potassium hydroxide are what you want
to use to raise your pH or to condition your pH.
As you're doing that, as you're adding potassium hydroxide and hydrated lime, you're not just
raising your pH, but you're also supplementing magnesium, calcium, and potassium, and helping
to keep those elements all balanced in your system.
That's it, short and sweet, as far as magnesium is concerned.
Again, make sure you get the deficiency key and you use it to diagnose, so that you're
being sure that what you're seeing is potassium, or magnesium, or calcium.
Remember.
They can look very similar, depending on the crop and depending on how they're manifesting.
Make sure you download that key.
If you like the video, please subscribe and check out the Vertical Food Blog.
We're going to be putting up a post with more details on managing magnesium and what to
look for when it comes to magnesium deficiencies.
Thanks for watching.