Hey again, it's Jason from Fraser Valley Rose Farm here today to ask the question
Do you have enough air in your potting soil?
If I was checking if I had enough air in my tires, I'd use something like this
But I couldn't quite find a way to stick that onto my nursery pot
So I've got to find a different method of checking how much air is in my potting soil
I'll show you that method here today
It's very easy, and I'm also going to explain to you exactly why it's important that you have enough air in your potting soil
So just a little bit of basic biology goes into this conversation in that the leaves of your plants use sunlight
and air
and water to make sugar and they send that all the way through to the tissues of the plants and when they get down to
The roots the roots are net
Consumers of those sugars they use that sugar to grow and to survive
So they need that energy and they take up that energy
They use that energy through a process called aerobic respiration or if you are a human you might call that
Breathing so they need to be able to breathe
They need sufficient oxygen around the root zone it
Through pockets of air so they can use that energy and survive and if they don't have it they'll die on you
So the properties if your potting soil then have to be able to deliver obviously
Nutrients and water but most importantly as well. They also have to be able to deliver air to your plant
so I'm going to show you how to test that and the way I'm going to do to do it is use a jar like
This now you can use any size of container and this size here. I'm gonna fill it with the soil and
The important thing about the container that you use is only that you know what this what the volume of the container is
You're just packing it not tight
You're not trying to push the soil in you're just putting in the soil the same way you would into a nursery pot as you
fill it with soil for planting and in this case, I'm just going to
Smooth it out across the top there. And the reason I like this one here is because it's exactly five hundred mils
I tested it. I measured it. It's exactly five hundred milliliters
so the measurement of the volume of this is important you have to know exactly what
Volume you're filling it to so that when you measure how much water drains out of it that you'll get an exact measurement
So what I'm going to do then is I'm going to fill this up
And fill all the air spaces with water then I'm gonna drain that and measure what drains out of it and in theory
Everything that drains out of it until it stops draining should represent the exact volume of the air
Filled porosity that's in that pot after you've drained the pot after irrigation
So once I get a percentage from that then I'll know if there's sufficient air in this potting soil
Let me show you exactly how to do it
Okay time for me to start filling this with water and the important thing about filling with water
Is I'm just not trying to displace all of the soil. I'm just gently
filling all of the air spaces between it
with water and
You may have to practice some patience during this step and I can see
bubbles coming out there and as all of the air that's in that soil profile is
displaced
And I'm gonna wait for the water to the drain and then pour in a little bit more
And if you look lower down on the jar now
I'm gonna point it out. You can see it's filling
When that reaches the top when I can see the top glistening with water and level with water
Then I'll know
All of the air spaces are filled
And that's it see just a couple of air bubbles there, but it's totally level to the top
and
So the same volume of soil is now filled entirely with water
and I've taken the top of this old peanut butter jar here, and I've also
Drilled a bunch of holes in it
So now that we've got it all filled and I'll tighten that on so it doesn't leak out the sides
Then I'm going to place it and measure how much water easily drains from this
Okay for the next part here
it actually seemed a little reluctant to let go of its air until I put a little tip into it like this and
I guess that makes sense to let the air come
in through some of those holes and as you can see
I hope you get this on the camera the air bubbling back up into the soil solution
Along the front edge of that jar
okay with the draining complete you can see the actual soil has lost a tiny bit of volume there probably a couple of tablespoons so
there may be a little bit of inaccuracy and the result because of that and the water that strained out is
125 milliliters, so if you do the division
What you do is you divide the drainage water by the original volume and that gives you a percentage in this case
125 divided by 500 gave me 0.25 or 25%
Air-filled porosity and that's actually a pretty decent number for a potting soil
This here is a sunshine mix
It's a peat and perlite based mix and so I would expect a really decent air-filled porosity there
So to give you some idea of what the right ranges are twenty to twenty-five percent might be a pretty decent range for a nursery
Potting soil any higher than I have to go to twenty-five and thirty percent
You're probably looking at a propagation mix something that you're using for
Starting it might give the roots a bit of a boost getting through this loose soil
But it will require more frequent watering and anything much higher than that and you end up having to water
Extremely frequently. It's going to get pretty hard to manage in a nursery situation
if you get much below twenty into that 15 or ten range that's going to be
Hard for your plants to get enough air to their roots
And so you may end up with problems with root rot. And so on through the growing cycle
So if it tests much below twenty, but preferably more towards twenty five
In that range is a pretty good one. I got to test a second soil here. Just this is my
This one here is my bark and and wood fiber based mix that I use frequently
I want to see what that one does. Okay. I filled the jar here with some of my
wood fiber based mix
This just composted wood bark and wood fiber that I get from a local supplier, and I'm curious to see
How it does so same procedure
take my time and
fill the whole jar with water and now once again with it all filled I can just
Drain it
Into this jar
Okay, and on my second soil here I've got the drainage water and it comes out as
110 milliliters. So again divide that by 500 and you end up with about 22%
Air-filled porosity which is still within a pretty decent range for growing. So I'm pretty happy with that
I hope that this has been a useful discussion for you
I'll add a link below that goes through some of those air-filled porosity percentages. I think quite nicely and sums up
what they mean if you do a test like this on your own potting soil and
Thank you so much for watching. If you have any questions, please leave those below the video