Hey, this is Nate Storey with Bright Agrotech, and today we're going to do a video on calcium.
It's the first of the secondary macronutrients, as part of our Plant Nutrients in Aquaponic
Systems series.
Calcium is super important in aquaponic systems.
It's one of the secondary macronutrients, so it's just one tier below our primary nutrients.
That's nitrogen, phosphorous, and potassium.
Calcium comes next, and it's right up there with magnesium and sulfur, among the secondary
macronutrients.
Calcium can be kind of tricky to manage because it interacts strangely with a few other things
in your system, including potassium and including magnesium.
The plant uptake of calcium is kind of different in some ways than other nutrients.
It's a little bit less passive, and calcium isn't actively moved around the plant.
We have to kind of know what we're looking for, and we have to know how to manage calcium
well.
Before I get too far into that, we need to talk about what calcium does.
Calcium is really, really important in the plant for regulating osmotic pressure, so
keeping the cells nice and full of water, and it's really important for holding cell
walls together.
Think of calcium as the glue that glues the walls of the plant cells together and keeps
them structurally sound.
It's a really, really important thing to the plant.
Usually when you start to have calcium deficiencies, because it is so important, it becomes pretty
clear pretty fast.
However, it can be confused with other deficiencies, so make sure you know exactly what you're
looking for.
Calcium is relatively immobile in the plant, so the plant doesn't actively move it around
as much as lots of other nutrients, so oftentimes you'll see calcium deficiencies start to show
up in the young parts of the plant first.
This, in most crops, is characterized by something called "tip burn."
You're looking for the rapidly growing portions of the plants, and they'll kind of turn black
and die back a bit.
That's really, really common to calcium deficiency.
Another thing, and lots of people have heard of this, is blossom-end rot on things like
tomatoes and fruits.
This is just, basically, not enough calcium and you start to see these necrotic, these
spots where the tissue is dead on the end of the fruit that the blossom was on, so with
tomatoes, you'll have this big kind of dead patch on the bottom, and it's similar with
other fruit and crops.
Those are the two most common symptoms to calcium deficiency, although there are several
others, so make sure you get the free key that we offer so that you can properly diagnose
calcium deficiency.
What causes calcium deficiency?
Usually it's simply that you don't have enough calcium in your water, so you don't have enough
calcium in your system.
If that's the case, there's lots of ways that you can supplement calcium, but we also have
to keep in mind that calcium interacts very strangely with some of these other plant nutrients,
and plants can't always discern the differences between, say calcium and magnesium and potassium,
so they kind of compete for the plant's attention, if you want to think of it that way.
Sometimes, we see calcium deficiencies when there's too much magnesium or too much potassium
in the water.
The same is true of ammonia, to some extent, but in most aquaponic systems, ammonia's going
to be at such low levels, ammonium, ammonia, that it's not going to interfere with calcium
uptake.
Nine times out of ten, the problem is actually that we just don't have enough calcium in
the system.
To confuse the issue a little more, sometimes we see calcium deficiencies when we've got
really low ventilation, or when our humidity is too high.
The reason for that is because calcium is moved into the plant as it takes up water.
If the plant's not losing much water, it's not drawing much water, there isn't a whole
lot of calcium entering the plant with the water.
If you think your deficiency is related to humidity or low ventilation, the easiest way
to deal with that is just to increase your ventilation or lower your humidity.
The next question is: How do we treat calcium deficiency?
If you think you have calcium deficiency, if you've downloaded the key and you're using
it to diagnose, and you're fairly certain it's calcium and not something else, there's
several ways that you can treat it.
I always tell people the easiest way to do it is just use calcium chloride.
This is calcium chloride, and this is a very common, very simple chemical to find.
You can oftentimes order really high quality laboratory grade calcium chloride online,
on Amazon, or something like that.
The standard for, say, tomatoes is to mix four tablespoons per gallon of water calcium
chloride, and then apply it foliarly.
I recommend people start with four teaspoons.
Four teaspoons per gallon of water, and you apply it foliarly, and if you start to see
results or if you don't see burning, then you can always increase your dosage slightly,
but I would rather that you just apply it more frequently in lower dosages.
The chances of you injuring your plants that way are much lower because different plants
react to it a little bit differently.
The important thing to remember is that this is a salt.
This is a salt.
If you're applying it, you just have to be kind of thoughtful about when you do it, and
like anything that you're applying foliarly, make sure you're doing it in the evening or
very early in the morning to reduce the chance of hurting your plants.
The other options, of course, are actually supplementing your system with more calcium.
This would include using things like agricultural lime to supplement calcium and magnesium as
you're raising pH.
That's primarily calcium hydroxide with some magnesium hydroxides in it, and also to use
chelated calcium.
You can use a chelated calcium product in your system that will help increase your calcium
levels.
It's a little bit harder to dose your system with calcium if you can't be testing it, so
if you have no ability to test your system and know how much is in it, it's typically
easier to add, say background levels of something like chelated calcium, or to simply raise
your pH consistently with agricultural lime, in combination with potassium hydroxide to
maintain proper calcium levels in your system.
Then, if you start to see any deficiency symptoms at all, you can always apply calcium chloride
to reduce those deficiency symptoms.
That's the brief explanation of calcium in your system, how to recognize deficiencies,
and how to deal with it.
If you have any questions, make sure you check out the blog.
We'll be writing a post on this with a little bit more detail for you.
Make sure you download the key.
It's free.
There's no reason not to use it to figure out what your deficiency symptoms are, and
what they can be attributed to.
Make sure you check out the website, and if you enjoy these videos, please do subscribe.