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Question for Al - Continued

Posted by briana_2006 (My Page) on
Sun, Feb 28, 10 at 22:11

Hi Al -

Sorry, I meant to hit preview and hit send instead.

I am curious if I could substitute horticultural perlite in place of granite?

Would that alter the characteristics of the mix too badly?

I have found the following potential sources for gran-i-grit:

This one has mica mixed in.

Here is another potential source - it seems this is only granite with no mica mixed in -

I can for sure get horticultural perlite locally. The granite I cannot seem to find locally. I would like to avoid shipping charges if possible.

And if it works roughly the same the perlite would be much lighter and easier to move the pot (see pruning advice post).

Thanks again for your help.


Follow-Up Postings:

RE: Question for Al - Continued

  • Posted by tapla z5b-6a MI (My Page) on
    Mon, Mar 1, 10 at 9:53

You CAN substitute, but Perlite holds considerably more water than granite, so you'd need to decrease the Turface fraction and increase the perlite. I know that sounds counter-intuitive, but Turface holds more water than perlite, so by decreasing the Turface and increasing the perlite, you'll be reducing water retention to approximately what the gritty mix would be.
3 parts bark
4 parts perlite
2 parts Turface

The granite would still be better, though. Where do you live? I might be able to help with finding the granite or a suitable substitute through one of my many bonsai contacts. It would help if you included your USDA zone and state in your user info (like mine > z5b-6a MI).


RE: Question for Al - Continued

I am glad that your (continued) question(s) have been answered.

The GW/FF does not permit editing.
It also forbids (rejects) a "quick" follow up post
by the same member in the same thread.

One general advice to (future) avioding 2 threads on the same subject:

One way around this, is to "re-post" with a (slightly)
different subject tittle, e.g.,
Question for Al -> Question2 for Al

RE: 2-Question for Al - Continued

Here is another example of how I did a quick re-post,
(without getting the "Message Rejected" thing).
Note the "2-" in the subject tittle.
Having one (1) tread on a subject is desired by all,
and is also suggested by GW.
We all live and learn...

RE: Question for Al - Continued

  • Posted by ejp3 7NY (My Page) on
    Mon, Mar 1, 10 at 20:09

Hey Al, I have access to and have the 3 gritty mix ingredients. Last year it worked for me but I just potted up 3 trees and my back is shot! I have a good source for coarse perlite that is less expensive than the grani grit or the turface. I see you recommend 3-4-3 Bark-perlite-turface as a substitute but you say "the granite would still be better though". Could you explain further? Also the turface is so much finer than the perlite or grani-grit that I wonder if it is in any way detrimental due to its fine texture. Thanks for your thorough explanations.

RE: Question for Al - Continued

Hi All -

Thanks for all the help, I really appreciate it.

Al - I am in the Saint Louis area.

I will need to look up my zone and modify the account to include this information.

Thanks again to everyone.

RE: Question for Al - Continued

  • Posted by tapla z5b-6a MI (My Page) on
    Mon, Mar 1, 10 at 23:34

Ejp - I like the extra weight of the granite because it helps eliminate blow-overs, I also don't have to screen it because it's prescreened. It works perfectly (for me and for most types of trees) at equal parts of all 3 ingredients, but the stark difference in water retention between the Turface and granite allows me to easily adjust water retention by increasing one or the other just a little while I go the opposite direction with the other, all the while keeping the bark fraction at 1/3 or less. More T and less G = more water retention - less T and more G = less water retention. You lose some of that adjustability by substituting perlite. Perlite also tends to float to the top. Try to get perlite that is medium in size - around 1/8" so it stays in the mix better if you use it. It helps to rinse perlite for plants that are sensitive to fluoride, too. (I don't know - so don't bother asking). Lol

Brian - you're very welcome. Hopefully, you can locate the granite near you. Shipping would be outa sight. You might be able to find cherrystone, too. It's mined in MN so I can see it coming down the river on a barge? Rural feed stores or elevators are the places to call.


RE: Question for Al - Continued

Hi All -

Al - I am happy b/c I believe I have found a local source for the granite (farm and feed atore - thanks for the suggestion!)
The place I called has 2 sizes available that are used with young and older chicks -- he said one is course sand size and the other is more like a small pebble. I will print the picture of your example and will have a look this weekend.

I am trying to find the pine bark fines - a nursery I have talked to here will have ~3/8 inch fines, which I believe is still a bit too large but is better than what I have. I believe the upper size limit is 1/8 inch?

Again,thanks for everyones help!

RE: Question for Al - Continued

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Mar 3, 10 at 22:24

If you're making the gritty mix, the 'ideal' bark size would be 1/8-1/4". I buy a Shasta Forest Products product (white fir bark) that is clean & prescreened in that size. I bought 20 - 3 cu ft bags in CHI last summer, so I have enough to last awhile, but all my friends keep moochin'. ;o)

I always used Gran-I-Grit in 'grower size' for the granite fraction, but in recent years I've gone to #2 cherrystone, which I prefer, but only because it's a rusty color and looks better in my bonsai soils. Performance is the same.

I don't know if the link to my Yellow Pages search will work or not. If it doesn't, just go to the Yellow Pages & enter the search words St Louis MO feed grain and you'll have lots of leads for the granite or cherrystone.


Here is a link that might be useful: Yellow Pages search

RE: Question for Al - Continued

If weight is a determining factor, Perlite could be substituted for the expanded shale.


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