What is the ideal size for drainage particles

[Gareth]

I've been experimenting with different medias, and I'm just wondering what everyone sieves their particles to.

I have used diatomite 2-7mm straight out of the bag for ages just sieving out the fine particles and dust so it doesn't clog. But even this is very course.

When I water it almost seems to go straight through with the majority ending up in the collection tube I have below ( on a third story flat so keeping the neighbors happy by not floods their balcony)

The mix still seems to retain a good amount of moisture, but I'm just curious what everyone sieves their course material to, weather it is diatomite, pumice, gravel, akadama or otherwise for their mix.

[daiviet_nguyen]

Good morning Gareth,

I assume your sieve and mine are the same: they have three size meshes -- largest, second largest and smallest.

For shallow proper bonsai pots that are around 30 cm (length or width) or above, the bottom layer are stuff that come out of the largest mesh. The second layer possibly the the mixes between the largest and the second largest. When I put trees in, I usually mix the second largest and the smallest. When the root balls are filled, I then usually use the smallest.

The bottom layers, I use mix of diatomite (experimenting with cat-liter too) and scoria.

For tall plastic pot, I fill the bottom layer with scoria that are up to 20-30 mm. Then another layer of scoria up to 10mm (these are imported from China by the big B stores.) Then as per normal bonsai pot.

A little while back, Bretts posted this article http://bonsaiwonders-art.blogspot.com.a ... ayers.html -- which I think warrants a read.

[kcpoole]

Diatomite / zeolite I use straight from the bag, No sifting or Washing. just rinse out after potting up.
This goes into every pot bigger than small shohin size as is, about 2 -7 mm in size.

the only time I seive is when washing old mix, I will us a 1 mm screen and discard anything that falls thru.

In small pots, I will sieve my mix to 2 - 4 mm for them

Ken

[daiviet_nguyen]

Also, a little while back, a member mentioned that sieving through dry diatomite and inhale its dusts is not good for our health. This makes perfect sense for me too. (But unfortunately I did a few times before )

For diatomite, anything that fell through the smallest mesh, I sieve them again through fine cooking sieve, purhased for $2-$3. This fine particle, I save for propagation. I still have a few litters of this.

[Craig]

I've been experimenting with different medias, and I'm just wondering what everyone sieves their particles to.

I have used diatomite 2-7mm straight out of the bag for ages just sieving out the fine particles and dust so it doesn't clog. But even this is very course.

When I water it almost seems to go straight through with the majority ending up in the collection tube I have below ( on a third story flat so keeping the neighbors happy by not floods their balcony)

The mix still seems to retain a good amount of moisture, but I'm just curious what everyone sieves their course material to, weather it is diatomite, pumice, gravel, akadama or otherwise for their mix.

Hi Gareth, this is what modern substrates are all about.They are able to hold enough moisture while not allowing water "pool" in the pot.Even a finer modern mix will drain through. Unfortunately not much can be done except add some more fines to the mix but the water will still run through.
If the water doesn't run straight through the pot, for "me" , it's not a great mix.

[Damian Bee]

I have been using a 5-20mm gravel on the bottom of my large pots and boxes to allow water to exit freely, as the gravel is large in size there is less chance of clogging with fines. I find it is also important to mix the layers a little to aid drainage. If the layers are not mixed a little you can get water tables sitting at the bottom of each layer which has obvious problems. Mixing layers together can be dependant on the materials you are using.
Although you can get away with one mix for all or most trees, I still believe that certain trees require specifics to grow in peak condition and certain mixes provide good results for certain types of trees, for example some Rhododendron species can handle a slightly finer wetter mix while for most Satsuki it is a death sentence.

[GavinG]

If the water runs straight through, why do you need a drainage layer? If the pot is only 2-6cms deep why do you need a drainage layer?

If your mix holds moisture well enough through summer, the particle size is OK.

I'm now mainly using 1-4mm pumice with coco peat. Drains freely, holds enough to get the tree through a summer's day. It's OK.

Gavin

[Gareth]

so what im seeing is people are using particles msotly between 2-7mm, with the majority being around 4mm.

So unsieved ok i guess, but i think im going to sieve to 4mm next time and see what result i get.

Thanks guys, just seeing what peoples thoughts were.

The main reason was i though it might not be good that it was draining straight through, is that the water may not have been spending enough time in the pot to absorb into the particles, it sounds stupid i know.

The other reason was, i live in a second story flat, and have to capture all my water so i dont shower my neighbours every time i water, therefore, if i utilize water better, the styro boxes underneath dont fill as fast, which means i dont have to bust my arse emptying them.

[Scott Roxburgh]

I use a 1mm, 4mm, and 7mm sieve.

The fines get used for cuttings, the 2-4mm for shohin, the 4-7mm for the larger stuff. Anything above 7mm (not much) is used as filler in the larger pots.