Any experienced folks here have any tricks when mixing their own soil blend? I have been crushing lava rock by hand with my trusty old hammer and hand chopping my pine bark with shears. I purchased my some of my raw materials from Lowe's and it's suitable, but not the ideal size.

It is a labor of love and I don't mind, however, any pointers to make it more effecient would be greatly appreciated. I have worked on it several evenings but it takes a long time to get it down to the needed sizes.

I have found that fullers earth or oil dry has to be natural and not breakdown when wet. next is industrial sand crushed granite or decomposed granite, sifted. and finally organic mixture peat,potting soil,added to your discretion but mostly less than 40 %

I am pretty happy with my components right now. I am using Calcined Clay (30%), Lava Rock (10%), Pine Bark (50%), and Pea Gravel (10%). I haven't narrowed down the exact percentages yet so that is just an estimate.

What I would love to hear would be some pointers to assist in breaking down the Pine Bark and Lava Rock to smaller sizes since I bought the standard bags. Some of the Lava Rock are the size of Lemons and I have been hammering them down to small pieces while using my shears to cut my pine bark. I have heard of some tricks, such as wrapping my rock in cloth, but I wanted to see if any of the experiences folk here have any great tips.

first thing first you have 80% moisture retaining material (i understand the percents arent perfect) .they calcine clay and pine bark are basically the same component you should be at about 30% of these 2 combined

any way i searched garadge sales for a good cheap food processor.dry out the bark and give a few pulses and your set. a sifter helps getting the chunks and dust out of the good stuff

as for the lava rock ??? maybe a bigger hammer

manofthetrees wrote:

first thing first you have 80% moisture retaining material (i understand the percents arent perfect) .they calcine clay and pine bark are basically the same component you should be at about 30% of these 2 combined

any way i searched garadge sales for a good cheap food processor.dry out the bark and give a few pulses and your set. a sifter helps getting the chunks and dust out of the good stuff

as for the lava rock ??? maybe a bigger hammer

Well i guess that isn't as good as I was shooting for then. I do actually want to retain just a bit more moisture than usual due to the extreme summer temperatures we get here (Beaufort, S.C.) but I don't want to stay at 80%. What other components would you recommend?

the components you are using are fine using calcined clay will retain more moisture than the pine bark its what i use one my shohin and mame trees. just be carefull in the wet months...
to be honest i have read that while doing expieraments a japanese bonsai grower (i forgot his name) actually had success growing trees in nothing but metal ball bearings so technically all you need is air,water,food and something to support the tree and the root stucture

Well that is reassuring...thanks. I figured since I have received a good response from my trees potted in the blend that it seems to be OK for now. That is pretty amazing about the ball bearings! When I first started researching bonsai I was surprised that the soil blends aren't really "soil" at all.

The more I research the topic it seems like it is a little more complicated than it needs to be. Yes, you don't want to use something too wet but as long as it allows drainage and airflow, you can use a multitide of different stuff. I think it's really more preference than anything.

one main thing i have learned over the years is for developing trees the granuals should be larger for root developement (1/4 inch+/-) more mature trees can be grown in smaller granuals(1/8 inch +/-)

Good to know! At least now I can justify some of my rock crushing skills and attribute it to a healthier environment instead of laziness...lol.

Crushing lava by hammer is way more work than I would ever put into my bonsai soil. Same for snipping bark by hand. I use pumice in lieu of lava, which I wash, but other than that I use it straight out of the bag. For bark, I use fine orchid bark (1/4"), bought in 2 cubic foot bags. Both are cheap from ly local farm supply and require little prep work before going into my soil mix.