Yes another soil mixture question

junmilo

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I've read books and read posts on here and Bonsai Empire. My question is can I just use "pumice, grit, peat moss" for a mix to use on Prunus spp, Satsuki Azaleas?? It's organic, holds water, holds Oxygen.

Thanks
 

Leo in N E Illinois

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Grit, I'm assuming crushed granite grit, is used mainly to add weight, and dry out a mix, as grit holds no water. It's structure is good, nice and angular And it doesn't break down. Not often used anymore, except to make a mix less water retentive.

Peat moss, this is a tricky material to use. Most commercial peat, usually from Canadian sources, is milled to a fine powder. This fine powder does not allow air to penetrate, especially after a couple years of use. If you sift a bale of Canadian peat, maybe 5% will be greater than 1/16th of an inch. The rest should be mixed into the vegetable garden. In the EU, if you can get German peat, it tends to be much more coarse, with less fines, a better addition to a mix than the finely milled Canadian product.

However, I have medium hard water, with near 200 ppm calcium, so peat is an excellent additive for acid loving plants. If I use peat in a mix, I try to repot every year, or every two years. This frequent repotting will help counteract the tendency of peat to have poor air penetration.

I would consider adding fir bark to your mix. It to will help with creating an acidic mix for azalea, and will hold it's structure for several years, 3 to 5 years.

You can use fir bark with or without peat. Myself, for azalea further along in development, I use no peat, just fir bark and pumice and kanuma. Yes, for near finished azalea, I spend the money on kanuma.
 
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Leo in N E Illinois

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For species totally intolerant of calcium, like blueberries, I use fir bark, peat moss, and hardwood sawdust. The sawdust is about 10% of the mix, and functions to feed the endo-mycorrhiza that blueberries depend on. With or without pumice. Nursery pots I skip the pumice. Bonsai pots this mix will be about 50% pumice, the rest will be the bark, peat sawdust blend.
 

GrimLore

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I have an azalea that I just use peat and perlite, grows well and tons of flowers!

I use the Canadian Sphagnum, Perlite, and whatever to keep it well draining, like Silica sand. Nothing fancy, works just fine, while satisfying the Azaleas PH needs. If you want the surface to look nicer simply add a top layer of crushed lava, your color choice...

Grimmy
 
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