Decomposed granite as substrate

[barrosinc]

A couple of respected bonsai makers in Chile use only sifted decomposed granite. They have great healthy trees.

We have scoria, perlite, pine bark, and others... all the fancy japanese substrates have forbiden entry.

I have been using pure scoria with good results but it takes me 10 hours to go and get scoria, then sleep in the car and drive 10 hours back.

It seems to be similar to chicken grit.

¿any ideas?

 

[River's Edge]

A couple of respected bonsai makers in Chile use only sifted decomposed granite. They have great healthy trees.

We have scoria, perlite, pine bark, and others... all the fancy japanese substrates have forbiden entry.

I have been using pure scoria with good results but it takes me 10 hours to go and get scoria, then sleep in the car and drive 10 hours back.

It seems to be similar to chicken grit.

¿any ideas?

We use turkey grit and chicken grit, granite grit in our bonsai mix all the time. I have not tried it as the sole component. I see no reason why it cannot work if one adapts watering and fertilizers to suit the overall objectives. Would have to be aware of PH factors, particle size to ensure some water retention and aeration. Then provision of regular nutrients with appropriate fertilizer.

 

[wireme]

A couple of respected bonsai makers in Chile use only sifted decomposed granite. They have great healthy trees.

When I first started I used granite as the main component, a little organic mixed in. Then a few years later added scoria, a few years after that went mainly pumice. Trees did just as well in the granite, possibly even better. I now try to make sure that I have at least some in the mix. I think there’s some beneficial minerals and things that become available to the tree from it. Possibly extracted to a soluble form by mycorrhizal fungi as a hypothesis of mine. Short story, in my experience the stuff seems to work well. The theory against it is that it’s not porous so doesn’t hold and release water vapours into the soil but... it worked.
Ah I see my reply got mixed into your quote, sorry.

We have scoria, perlite, pine bark, and others... all the fancy japanese substrates have forbiden entry.

I have been using pure scoria with good results but it takes me 10 hours to go and get scoria, then sleep in the car and drive 10 hours back.

It seems to be similar to chicken grit.

¿any ideas?

 

[bonsaidave]

I would think watering would be a bitch.

 

[River's Edge]

I would think watering would be a bitch.

Specially in Texas,California,Arizona, New Mexico etc. Probably not enough time off to replenish Shiner's.

 

[hemmy]

We have scoria

Scoria, but no pumice? You are on the Ring of Fire! Here’s a lake of pumice only 12hrs south!

Seriously though, Chile mines a lot of pumicite, you may also have larger grain pumice being used for construction. You also have diatomite mines, any diatomaceous earth to use for substrate?

 

[Gsquared]

I’ve used decomposed granite in the past. It was all the rage in the San Francisco club in the late 90s, especially for California junipers. Most would mix with scoria and a little bark, but some people used it straight. I like the way it looks, so used it as a show dressing. Using it in a mix or alone made for one really heavy pot! It is useful for cascade styles because it is so heavy and helps keep pots from tipping.

 

[Anthony]

Makes, acid lovers ill.
Tested on Tamarind, didn't like it.
Good Day
Anthony

 

[GGB]

I used some 50/50 with akadama on a handful of trees. I don't like the way it looks (that's irrelevant personal opinion) but I always figured it was to heavy and not porous enough to use alone. But apparently it's fine (others above me). You shoukd give it a shot. It will be very dry. Even if you mix it with your other stuff it's good cheap filler so, less ten your drives

 

[Bonsai Nut]

Nothing "wrong" with it - but it isn't porous like many other soil components. I think the tendency would be to go with smaller particle size because of the lack of porosity - reducing the oxygen in the soil mix. There might be an increased chance of water pooling or necrotic zones in your soil as a result. Just something to keep in mind as you use it.

 

[Dav4]

I got rid of it years ago due to it's weight... absolute killer in large pots.

 

[wireme]

It’s a bit ironic that the first season I replaced granite with pumice my trees suffered from underwatering, similar particle size, same watering schedule. I discovered that while I didn’t necessarily have to water more often I did have to water more thoroughly and for longer each time. If pumice gets a dry interior and you just quickly pour water through the dry interior pulls the moisture in and you’re almost dry again right after watering. I was used to non porous substrate that didn’t do that. At least that’s what I think was happening, it’s all a few years back now, memory like a bunny tail.
I totally agree with the weight comments! Heavy.

 

[Melospiza]

It’s a bit ironic that the first season I replaced granite with pumice my trees suffered from underwatering, similar particle size, same watering schedule. I discovered that while I didn’t necessarily have to water more often I did have to water more thoroughly and for longer each time. If pumice gets a dry interior and you just quickly pour water through the dry interior pulls the moisture in and you’re almost dry again right after watering. I was used to non porous substrate that didn’t do that. At least that’s what I think was happening, it’s all a few years back now, memory like a bunny tail.
I totally agree with the weight comments! Heavy.

On Harry Harrington's book, he talks about watering twice, with a 5 min interval in between to get a more uniform wetting of the soil interior. That's what I do now.

 

[wireme]

On Harry Harrington's book, he talks about watering twice, with a 5 min interval in between to get a more uniform wetting of the soil interior. That's what I do now.

Yeah I now do something like that as well when possible, sometimes, just trying to water and get to work on time.. you know. But it’s a good suggestion, good practice to follow, it helps
I also like to do just a quick surface moisten on occasion when the main body is still moist but the surface is getting dry. A quick light pass over the surface, deep watering later. I often do that towards the end of the day and then real watering in the morning.