Hey again, it's Jason from Fraser Valley Rose Farm today
I want to talk to you about how to improve the drainage both in your containers and out in your garden and
Frankly, I have no advantages that way. My garden is on heavy Nicomen island soil, which means it does not have perfect drainage
And so so many plants say "prefers
Well-drained soil" or doesn't like "wet feet" and so I have to do something to improve that
I'll go through that with you today
I have a couple of demonstrations to take you through that will make it so much easier to understand so stick with me through that
First up is a test to check the drainage on this peat moss and perlite mix
it's six cups in total of the mix and I'm pouring in two cups of water knowing that the potting mix will hold some of
that moisture and then I'm measuring how long it takes to release a half a cup into the drainage and
The result here you can see is that it takes about a minute and 20 seconds to drain a half cup
Next if I do the same thing
With a coarse gravel and it shouldn't surprise you at all that the gravel doesn't hold any moisture and doesn't fold it back much
So it really drains through
Entirely in less than about five seconds this none of this should be surprising us here finer materials with more water holding capacity
Will slow down and hold more water while coarser materials with more airspace will allow the water through faster
so potting soils with more peat moss or coir or
That's coconut fiber or finely composted or shredded wood fines
Will drain slowly while potting mix with larger bark chunks and ingredients like coarse perlite vermiculite
Charcoal or pumice will be faster draining so pretty basic, right?
Let's see what you make of this one for my next demonstration
I use the same container with the same potting mix at the top
But I place a generous layer of the coarse gravel at the bottom of the container
So the question being will it drain fast like the gravel? Will it drain slower like the potting mix or?
Somewhere in between but actually as I test it
It becomes clear very very quickly that it is draining slower than either one
in
Fact by the time it reaches one minute and 30 seconds
it's basically stopped draining and I have to add another cup of water just
To get it to finish and get me the half cup of drainage. So what happened here?
Well, this is not a new experiment
this has been done for a long time in soil science and what they found is that when you combine a
Finer textured potting mix up above and a coarser textured layer down below
That it stalls the drainage process up above in the finer textures peat and perlite
layer
It actually absorbs more of the moisture
Holding it and released not releasing it very readily into a coarser layer down below
This goes against what traditionally was thought of in horticulture where they would throw rocks or stones
Or other coarse material in the bottom of pots to try to improve drainage
So I can tell you a few things about improving the drainage in your containers and nursery pots already
first of all choose a potting mix that has a good amount of
coarser material in it things like those coarse chunks of perlite or vermiculite
Ii do not layer with a coarser material at the bottom of the pot any of those interface layers
That change the texture of your soil will tend to disrupt drainage and third of all use a taller and narrower
Container rather than a wide or shallow container the wide and shallow containers. The low ones tend to hold more moisture
per the soil volume now, you may wonder what are the succulent growers doing growing in shallow containers then well the reason is because
Succulents actually have very shallow roots. So placing them in a tall container would be a waste of space
but they get away with it by using a particularly coarse potting mix to try to improve the drainage and
now moving on to a discussion of
drainage in the garden or outdoors
I'll do one final experiment here and it involves pulling some soil from my garden
Now I mentioned at the beginning of the video that I have heavy Nicomen island soil and I'll show you how it drains
So I'm placing that in the bottom of the same container in place of the gravel and placing the peat based mix above
And let's see how it does
So it's becoming clear quite quickly here that my garden soil is no champ when it comes to drainage
In fact, it's lows right now
Just like we did with the gravel and I have to add another cup of water just to get it to finish
In the end. It's the slowest timed of everything. I've done so far
So, what does that mean for drainage in my garden before I go with too far into recommendations in the garden
Let me go back and amend that list of recommendations for containers and say that garden soil is not great as a potting mix
first of all, it's far too heavy and as in the case of my garden soil
It doesn't drain all that well back onto the garden here
Let's look at the hole that that soil came from and yeah
you can see this is a heavy slick garden soil and
Just replacing that soil in the planting hole with something that's better drained
As you can see for the demonstration isn't going to solve your problem. In fact out here in the garden. It's much much worse
Because when I normally get rain here the water
Collects at that top layer of the soil and then just slowly percolates down through the profile
But in effect by creating a hole with a coarser more well-drained material in it
You've created a drain a drain to nowhere, but a drain nonetheless
so all of the runoff from the surrounding soil now is going to collect into that hole and
waterlog the roots of your plant
This is why I prefer to backfill with the need of garden soil for my plantings with no major amendments in the planting hole
The more similar the soil is in the planting hole to the surrounding garden soil
the less weird layers and drainage I have to contend with
If I improve the soil with organic or other amendments to improve drainage
I could be creating a larger problem for the plant and its roots
I'm also in favor of a modest
Tamping down of the soil after planting to simply restore the soil in the planting hole
To a similar firmness and compaction to be consistent with the surrounding soil so it doesn't become that drain
Now I can imagine some objections to my point of view after all don't we want to give our Gardens the best possible start?
Don't we want to give them a dedicated area where they can have a loose?
Uncompacted planting soil something with lots of organic matter and fertilizer in it. So the roots don't have to go searching
Anywhere. Well the truth is when you're making a planting you want the roots to go looking you want to go looking for water you
Want to go looking for fertilizer
so I really do recommend that you use the native soil and if you want to make some
Improvements you improve the entire garden from the top down
Rather than just hitting at planting hole by planting hole
So let's talk about the improvement of heavy and modestly slow draining soil with other clay
characteristics that you'd like to improve
So I've done a whole other video on the topic of improving clay and heavy soils, which I'll link above
one option is to add organic mulches to the entire area which will improve the structure and workability of the soil as
It slowly breaks down these mulches also protect the top layer from the drying
and crusting that are sometimes present in clay soils
Another option is to plant mixed cover crops as a green manure and for their clay breaking roots
I also have a video discussing the option of incorporating sand into some depth at the top profile of the soil
It's not exactly my first option. But if you want to hear a discussion on that method I'll link that video as well
It's important
However to note that if you're really dealing with a serious drainage problem
like
Consistent puddling and a deep layer of low permeability soil like clay the measures I just mentioned probably will not solve your problem
Improvements at the surface like mulch or green manures can just as easily end up waterlogged
themselves under water
if you do incorporate sand to a certain depth
You may be able to move some of the moisture down a little bit lower and if you have shallow rooted crops
That may solve your problem
well, let's talk then about some of those most difficult drainage areas where you have standing water or puddles for a good portion of the
Year, and in that case, I can't think of anything better than a French drain
So remember I mentioned the you dig a hole and place a coarser material in it. It will collect water from the surrounding
area well
if you do the same thing with a trench and fill it with the coarse material and have a
pipe at the bottom of it that is a French drain and you can redirect the water away from your troubled areas into
A lake or a pond or another area for drainage you obviously for best ascetic effect
We'll use the French drain with gravel or something like that
Or if you don't mind the way it looks you can just use
contours in your landscape and keep an open ditch to carry the water away as well and
What else could you do well in my area even though we have a fairly heavy soil one of the main crops is blueberries
Which actually prefer a decent drainage around their roots and you can see what they've done here
They've caught toward the land to create hills and valleys the hills for the rows of blueberries
Now this may not solve the worst of the drainage issues
But it does at least allow the shrubs some area for their shallow roots to escape water logging
You could emulate this in your garden with raised beds or if you don't care for the wooden frames
Which can sometimes be susceptible to rot against moist soil?
You can go for the no dig style of raised mounds and you can see this demonstrated on Charles Dowding's Channel
Okay, that's it from me on how to improve the drainage of your soil
I hope this answers some of your questions and if you have any further questions on the matter or some comments
Like if you've had some success in this regard and want to share that I'm sure everybody would appreciate you leaving that in the comments
Below. Thank you again for watching