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Layer of Drainage advice

Posted: September 14th, 2018, 4:59 pm
by annaf
I am new to the group and to Bonsai,

Can I ask what ppl use on the bottom of there bonsai pots, I am in Melbourne and am getting very confused on what to use, do you use such as lava rock, scoria, gravel, grit, and where to buy it. I went to a local Mulch supply and the gravel I purchased seemed ok but when I rinsed it, it was full of cloudy water. Would appreciate any advice, I am new to bonsai, I have a few Jade, Junipers.

Very much enjoying the forum :)

Re: Layer of Drainage advice

Posted: September 14th, 2018, 6:00 pm
by shibui
You will find that there are many experts in bonsai and all have slightly different ways of doing the same thing. That does not mean some are wrong, it just means that plants can survive all sorts of abuse.
There are 2 schools of thought on drainage layer. Some growers still use the traditional method of a coarser grade of their chosen potting mix at the bottom of the pot. Most, including me, don't use any drainage layer. There is evidence that a drainage layer actually impedes drainage and can result in waterlogged root zone.
My advice: Just start with your chosen potting mix (still use mesh over the holes so it won't all fall through) place the tree in position and top up with more of the same potting mix. Works for me.

Re: Layer of Drainage advice

Posted: September 14th, 2018, 6:43 pm
by Daluke
Anything coarse which doesn’t break down is good.

Gravel, grit, lava, scoria, pumice, pebbles, broken glass, crushed brick... use your imagination anything that when compacted has some gaps in between works.

The drainage layer though does not in fact help drainage. It helps oxygen get to the roots and “breath”.

In turn this helps promote growth.

Re: Layer of Drainage advice

Posted: September 14th, 2018, 7:09 pm
by annaf
Daluke wrote:Anything coarse which doesn’t break down is good.

Gravel, grit, lava, scoria, pumice, pebbles, broken glass, crushed brick... use your imagination anything that when compacted has some gaps in between works.

The drainage layer though does not in fact help drainage. It helps oxygen get to the roots and “breath”.

In turn this helps promote growth.
Thanks for your advice, l have heard it’s more for the roots to breath than drainage.

Re: Layer of Drainage advice

Posted: September 14th, 2018, 7:11 pm
by annaf
shibui wrote:You will find that there are many experts in bonsai and all have slightly different ways of doing the same thing. That does not mean some are wrong, it just means that plants can survive all sorts of abuse.
There are 2 schools of thought on drainage layer. Some growers still use the traditional method of a coarser grade of their chosen potting mix at the bottom of the pot. Most, including me, don't use any drainage layer. There is evidence that a drainage layer actually impedes drainage and can result in waterlogged root zone.
My advice: Just start with your chosen potting mix (still use mesh over the holes so it won't all fall through) place the tree in position and top up with more of the same potting mix. Works for me.
Thanks you for replying, it’s good to hear what ppl are doing, l guess it comes down to what works for you,

Re: Layer of Drainage advice

Posted: September 14th, 2018, 7:11 pm
by annaf
shibui wrote:You will find that there are many experts in bonsai and all have slightly different ways of doing the same thing. That does not mean some are wrong, it just means that plants can survive all sorts of abuse.
There are 2 schools of thought on drainage layer. Some growers still use the traditional method of a coarser grade of their chosen potting mix at the bottom of the pot. Most, including me, don't use any drainage layer. There is evidence that a drainage layer actually impedes drainage and can result in waterlogged root zone.
My advice: Just start with your chosen potting mix (still use mesh over the holes so it won't all fall through) place the tree in position and top up with more of the same potting mix. Works for me.
Thanks you for replying, it’s good to hear what ppl are doing, l guess it comes down to what works for you,

Re: Layer of Drainage advice

Posted: September 15th, 2018, 6:56 am
by MJL
I am no expert but a drainage layer at all times for me.

I've always put drainage layers into my normal potted plants and now I have transferred this habit into bonsai. I generally use stones with a size matched to the pot I am using at any given time. I get a sense of comfort from seeing water drip from my drainage holes ... (on my bonsai people!! :palm:) ....

I also find it easier to repot bonsai with drainage stones because I find that I can tease out and then trim the base roots easier when I do repot.

Each to their own.

Re: Layer of Drainage advice

Posted: September 15th, 2018, 10:56 am
by treeman

Re: Layer of Drainage advice

Posted: September 15th, 2018, 1:35 pm
by MJL
treeman wrote:I touched on this subject here..viewtopic.php?f=12&t=24510&hilit=+drain ... tion+layer

Thanks - that's a very good thread that Treeman points us to. I now understand the concept of an aeration layer, at least at a superficial laymnn level. I also understand the concept of drainage manipulation as noted by Bretts in the tother thread. Good stuff - thanks for passing on the knowledge.

Re: Layer of Drainage advice

Posted: September 15th, 2018, 2:27 pm
by annaf
treeman wrote:I touched on this subject here..viewtopic.php?f=12&t=24510&hilit=+drain ... tion+layer
I had ready that article, interesting read, thank

Re: Layer of Drainage advice

Posted: September 15th, 2018, 2:28 pm
by annaf
MJL wrote:I am no expert but a drainage layer at all times for me.

I've always put drainage layers into my normal potted plants and now I have transferred this habit into bonsai. I generally use stones with a size matched to the pot I am using at any given time. I get a sense of comfort from seeing water drip from my drainage holes ... (on my bonsai people!! :palm:) ....

I also find it easier to repot bonsai with drainage stones because I find that I can tease out and then trim the base roots easier when I do repot.

Each to their own.
Thanks for your feedback,

Re: Layer of Drainage advice

Posted: September 15th, 2018, 5:36 pm
by Dean
I only use a drainage layer in cascade pots because my normal mix is very free draining.

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Re: Layer of Drainage advice

Posted: September 15th, 2018, 5:55 pm
by Shagga
Hey everyone

The way I see it and I ain’t no expert is that when you flood the soil as it drains through to the bottom it sucks fresh air down from from above. Once this process is done the roots suck the moisture from the soil and having a drainage layer makes it possible for air to come from above as well as up through the drainage holes.
This is just my assumption...
In saying this I’ve used drainage layers when I had something to use and if not mix straight in on top of the screens and I can’t tell you for sure based on my experience if it makes any difference but I think it makes sense I guess. :lost:

Chris