AusBonsai

has anyone ever used or does anyone use blue metal for a soil component??

i have heard mixed responses and am testing it myself.
i use 7mm seived into 3-5mm and then the bigger stuff thats left im using for my bigger trees...

can anyone already tell me any results for ugrowing in this medium??

Fly Bri Used this stuff for a while, until I kept bagging him about his ugly soil.
I must admit though after finding out he used it. I found it very handy to shovel some up from a newly lanscaped area that I had an abundance of 5mm blue metal when I had run out of other medium to use in my mix.
As a grit is seems to work fine. But a grit like this or any other solid grit I class as space filler. It helps to establish a free draining soil but it just takes up too much space in the pot. A much better idea is Zeolite, Diatomite, Scorcia or Appugulite clay.
But Blue metal has worked if that is all you have available at the moment

cheers soltan

I have not used it as a soil component, but I have used it as a pot liner to cover the holes in the bottom of the pot (Plastic Grow pots).

Just like Scoria, I cannot find it in small enough sizes, 10mm is the smallest grade, and it is Much heavier than scoria.

Ken

Lee Wilson the president of the AABC has been using it for years he calls it road base.
When we were in Canberra this year he did a demonstration on a big JBP he had been growing it in it for 28 years. I asked did he wash it as when the nursery man I used to help got it we had to wash the dust out.
It work looks ugly but if you cover it with the Aquarium gravel it looks good. Pup

There was a lot of it in the soil that I used to use. I found it incredibly heavy, especially as I have rather large trees and pots. I think it also screwed up the pH balance of the soil in some of my trees as they became sickly and died, over a 6 month period. I'm no fan of it.

which trees in particular hector this concerns me

i have pines, tridents, Japanese maples, elms, and others in it...

does it take the ph too far alkaline

I have used Koreshoff 'road base' mix since I started bonsai and now use Lee Wilson's slightly coarser grade. I prefer the finer but the plants don't mind. The medium has about 10% humus and some fertiliser mixed in and is wonderful on ALL plants. I have been scorned for this type of soil until the scorners repeatedly saw my various trees over the years and whether they are natives, azaleas, junipers, olives or what... they are vibrantly healthy. Having said that, I do gather that different climatic conditions can affect its quality. In my Sydney region it is great... you cannot overwater a tree and it retains moisture within reason. In a drier climate I have been advised it dries too quickly. But it allows a lot of air into the soil to promote healthy root growth, curl grubs cannot survive in it, unfortunately weeds can and do. I don't find it ugly. What an odd comment. Moss will grow on it, it is little different from a pot covered with dressing stones.

I have wanted to change due to the one major disadvantage and that is the WEIGHT of it... heavy. But my trees are so happy in it that I have moved to smaller trees/smaller pots to retain the road base.

I for one heartily endorse this.

'Soils aint Soils, Sol'

There are so many soil recepies and additives on the Internet that my head spins, but I do agree with Hector on the road base issue (Blue Metal) in as much as it just makes the pots too damn heavy. I preferr crushed granite, a lot lighter and even more sharp than blue metal and it looks good as well.

Jon

MelaQuin wrote:I for one heartily endorse this.

thanks... i have heard you talk about these really coarse soil mixes since i was involved with clubs, and since i have made the switch to coarse, i don't thnk ill go back

i have been experimenting, and so far, i think it's because of the surface area and especially the air, but my trees are really liking the blue metal

im using about 90% blue metal, 5% cow poo, 5% coia peat... it's workin fine

oh, and i don't mind the weight, it's less time i have to spend at the gym... and whoever knows me personally, knows my pots are already heavy

How long have you been doing this Aaron?? I'll prolly start in spring.

I have been using Lee Wilson's gravel 50% with Ray Nesci's mix 50% with added blood and bone to the recipe. All trees are healthy and good colour, especially conifer species. Occasionally when I feel the urge I will also add zeolite. Generally I find that the more gravel in the black pine ix the better.

John T

I have been using a mix of 25% 3mm-5mm blue metal, 25% Zeolite and 50% good quality potting mix and everything looks fine. I add osmocote to the mix when repotting.

It is a heavy mix but the trees do well in it.

After seeing a Satsuki Azalea growing in Kanuma soil (demo tree by Arthur robinson of WA) I have never seen such a healthy tree and I will use Kanuma for the azaleas from now on.