Have you got mineral deficiencies on your lettuce? This is what we're going to
see together in this video.
[Music]
So I received an email from Nitish who has some issues
apparently on the growth of his lettuce and he sent me some pictures to have my
opinion on the health of those lettuce. So before trying to find an answer for
Nitish, and it's going to be challenging, I just want to explain to you what is the
idea with deficiencies in aquaponics. So we are growing food in aquaponics in a
closed environment and the only media we have is scoria, which is a volcanic rock.
I mean, scoria here in Melbourne Aquaponics, but you can also use clay
balls. You can use gravel, plenty of different media are available, but for me
the cheapest one here in South of Australia in Melbourne I really believe
that is the scoria because it's a volcanic rock. It's very cheap and it has a very high
surface area. Anyway, the purpose of the media is to increase as I mean to
offer a good surface for the bacteria to live on. So we got our grow bed here that
is full of media of those rocks. Right now the issue that we have in
aquaponics is not really sure that's a little challenge is that there are no
minerals that are added in the system and we always grow plants and we
harvest plants. So those plants are absorbing the few minerals that are in
the water at the beginning. Obviously, every day we are feeding our fish. In the
fish food there are some minerals. There is potassium. There is calcium.
There are a bunch of minerals but there are some minerals that may be deficient depending
on the quantity of and the biodiversity of
food that you are growing. If you are growing a lot of plants that need a lot of iron
for example or potassium, you may have some deficiencies. So when you grow your
plants, you may find some leaves that are turning yellow or they're looking a bit weak and
that may be due to the fact that you are light in one type of mineral. So some
expert gardeners apparently they would be able, by looking
at the plants, to tell you exactly what type of mineral is deficient. I will be
very honest with you. It is not my case. Very, very difficult to tell exactly what
type of mineral is deficient just by looking at the plant. There are some
tendencies. Sometimes you can see the plant that is going gray from the
side of the leaf. Sometimes it's through the veins. So I'll give you some
ideas, but it's always very, very tricky to say exactly, "Ah, I can see that the leaves and I
can tell you that's potassium deficiency." By the way, if some of you are able to do
that, by looking at the picture, please give the response to Nitish because
he's wondering what is the problem with his lettuce. When I look at the picture,
I can see that obviously the old leaves are not looking good but for me you know
it always happens when you are growing green lettuce. These young leaves are always
growing, growing. And after a while I see old leaves. They get a bit older
and they just die off while the young ones are growing again. It's a normal
cycle. It happens every time. When you go to the supermarket, if you don't see old
the leaves that are dead, it is because they have been cleaned before being harvested.
So for me, it's a normal process to see the old leaves a bit gray.
Now, obviously, from the pictures we can't tell much, but if the young leaves are
also deficient, if they are not nice green but they are a bit yellow, yes, you
may have a deficiency. So then it's very tricky to tell you just by one picture
what is the deficiency. So first you need to look at the quantity of sunlight that
is available for the plant. You know, every plant needs a certain
intensity of sunlight. If they don't have enough sunlight, they may not develop the
best color and they may not give you the best productivity, the best growth. Then
you got the temperature. You may have issues with temperature. Then you
have nitrogen. You need to make sure you get enough nitrogen in your water
for the plant. It's always tricky to know because sometimes as soon as the
nitrogen is produced, thanks to the bacteria, and when I say nitrogen, I'm
talking about nitrate. Sometimes as soon as it's produced, it's consumed by the
plants. So you don't really see the high level in the water and you don't want to
see high levels in aquaponics because we have fish. It's very different from
hydroponics where we can allow ourselves to go to high concentration of nitrate.
We can go to 300 ppm, 500, even more depending on the species we want to grow.
Here in aquaponics, we don't want to go above 5000 because then obviously
the fish wouldn't be in good conditions. So we have to be careful of
this, and it makes sense that we can't be in the optimum of the plant, but we can
give a good substrate for the plants for them to grow nicely. So nitrate is one of
them and then you got all the minerals. So I was talking about minerals. So
obviously, calcium, potassium. Well, anyway, you got 12 minerals that are very important
and then you got all the minerals that are also important in smaller quantities.
So it's always very difficult for me to respond to those type of questions.
Iron is one of those minerals that when you put it in aquaponics,
because of the presence of oxygen, the water and the pH you always
got the iron that is turning into rust. You got oxidation and becomes
unavailable for the plants. So it's always a good idea to add a bit of
chelated iron if you see some deficiencies on your leaves is the
first thing to do and also to add a bit of rock dust or other mix of minerals
that you can buy from any gardening shop. This is going to help you to hopefully
fix this deficiency problem. Also if you are growing the food,
your plants in a greenhouse, sometimes you got too much moisture and it gives it
helps some molds to grow, some type of fungus. So in this case, there is no
need to add more minerals. It's just because you got too much moisture in the
greenhouse. So you got multiple quantity of factors.
You know, it's not just the plants. It's also the environment. We need to know how you
are growing the plant, in what type of environment. Is it in a greenhouse? Is it
full sun? Is it full shade? What is the temperature? What is your nitrate
level? What type of plants are you growing with it? Is it only one type?
Or is it a lot of plants? You know, it's quite tricky to respond to this
question just by seeing a picture, but I hope I gave you some good tips to have a
look at the different parameters and trying to find what can be the issue for
you, if there is an issue, right, because from seeing the picture, I don't see a
massive issue. I see that the old leaves are not growing well, but it's very hard for
me to tell if the plant is growing well or not. You know if you see if it's
producing or if it's not. Also here in Melbourne right now, we are in the
beginning of spring. The temperatures are not very high. So during
this time of the year, you can't expect a high productivity. It's going a bit slow.
It's producing but it's a bit slow. So you got all those parameters to take into
consideration. So Nitish, I hope it helps you and please give us your comments in
the video, yeah, below the video. Anyone, you can help Nitish, if you have
any idea, any feedback to give. It's in the comments of the video. If you want to
start aquaponics, you can have access to the six-step process to build you own
aquaponics system. It's a free training that is available in the description of the
video just below. I give you some tips and I give you the ratio to expect, the
limit to expect when you want to build your aquaponics system to build it in the
good conditions to make sure that you are going to avoid common mistakes and
that you're going to maximize the productivity of the system. If you
enjoyed the video, please give it a like. It really helps the channel
and also you can subscribe. I'll see you in the next video. Bye-bye. Don't forget to
get your free gift from this screen. You can also leave me a comment below the
video. Subscribe to the channel and see my last video. I really hope to see you
soon, and I wish you a fantastic success with aquaponics. Have a good crop!