What Soil Do You Grow Out In?

BonsaiBen

What soil do you use to grow your pre-bonsai in when developing in a big pot? I am growing some of my trees in large terra cotta pots (in lieu of being able to plant in the ground) and had previously been told that good bonsai soil was not neccessary because the depth of the pots gives much better drainage than shallow bonsai pots. I potted my trees with a small amount of old bonsai soil mixed in with potting soil, thinking that the high organic content in the potting soil would help them grow faster. Now I am begining to believe that this was a bad move based on some reading I have done about why roots like coarse materials. Any advice would be appreciated.

Ben

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TreeBay

This might have been the link you were talking about.

However, there is nothing there about "high organic content in the potting soil [would] help them grow faster" though. That does sound mythic to me.

http://forum.bonsaitalk.com/showthr...=&threadid=6074

>Now I am begining to believe that this was a bad move based on some reading

Ben, what info have you been reading? It always helps to provide the full story. We do see a lot of "I have heard" and "I have read" and it can be difficult to understand what someone means. It is much more useful to discuss specifics.

Regards,

Matt

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BonsaiBen

You are right, I should share what led me to this idea and what I have been reading.

I was put under the impression that the potting soil would be good for its organic components from advice on another bonsai forum last year. I know, take advice for what its worth.

Now the info that is making me regret my soil decision is fromThe Bonsai Workshop by Herb Gustafson pp. 91-93 where he talks about particle size, texture and soil composition.

TreeBay

I'll see if I can find that book. Finding a soil medium that works for you is a fine-tuning process, and you do have to start somewhere. If you are getting warmth, moisture and the diffusion of air into the soil, and if it drains reasonably well it should be a workable mixture. Organic material will break down pretty quickly and impede drainage. Even softer inorganic materials will corrode by erosion and action of the roots.

I think I mentioned in that linked thread above that I used the organic part mainly as a mulch in the top bit of soil. It might not be a good idea to use a high-organic potting soil for projects that are going to go awhile between repotting. You are almost certainly good for a season though if you keep an eye on it. It can be more disruptive to repot unnecessarily.

How big are your containers? Do be sure to add some blocks or supports (feet) under the terra cotta to make sure they drain freely. If the hole sits right on the bench, it won't do too well.

Regards,

Matt

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BonsaiBen

Thanks for the advice Matt. My elm is in something that seems to be about five gallons and it is on my iron slatted fire escape so the water flows right down to the street when I water it. My juniper is in a slightly smaller container, about two gallon size.

I would repot them next year anyway--I pretty much wanted to know if they would make it through the year like this.

If I put the juniper in a larger pot and dont cut the roots, just wiggle the free soil off them, and add inorganic material would that be safe? Gustafson reccomends that junipers be potted in 75% inorganic material and it currently has hardly any.

BonsaiBen

Since there have been no replies other than Matt's, I am assuming that everyone here uses their regular bonsai soil mix to grow out their pre-bonsai?

Ryan

I believe Ben may be referring to some a discussion over at bonsaiweb. When I am growing my stock I first grow in 50/50 peat and perlite. I grow this stock in large (5 gallon or sometimes more) until I am ready to begin training it. When I start training I use shallow bulb pans and my regular bonsai soil. The soil requirements for growing in a small bonsai pot or even a bulb pan are quite different than growing in a large nursery container.

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BonsaiBen

Yea, but I likely didnt remember exactly what you said about your soil mix as I didnt add any perlite or any other drainage material. I assume you use this peat mix for the cost of it as opposed to a regular bonsai soil mix? The reason I am a bit concerned about what I am now using is because it is staying damp for quite a long time without drying out.

BonsaiBen

Actually I went back and found the thread that put me under the impression that I could grow out my elm in potting soil. It wasnt the one where you (Ryan) gave me great fertilizing advice this year. I pretty much recalled the advice that I was given incorrectly. Duh.