What grade soil would you use

[Bretts]

I was recently sifting some used soil. This soil is a mix of various components that I have used over the last few years.
The pile on the left went through the larger bonsai sieve but not the medium one giving a size of about 4-6mm the pile on the right went through the medium sieve but not the smallest sieve giving a size of about 2-4mm the pile in the middle is a mix of these two grades giving a size of about 2-6mm
What grade would you use in a medium sized bonsai pot of about 250mm.

soil2.jpg

[Bretts]

Hmm 25 views and only 3 members know what grade they would use
It is not a hard question

[alpineart]

Hi Bretts , mate i use the same blend for all species . It is a blend of 2.5mm -8mm. As for the sifted fines i use them in seed raising mix same blend as bonsai mix but only the fines , or blend them in with the 8mm+ material and use it in the grow beds . Most people would only use 2-6 at a guess, however i have tested my blends continually for many years , on average of 4 different blends per year for the last 15 +years , works out to be a lot of testing .

However none of my mixes have contained any Normal recommended bonsai mediums all are local garden center materials or collected as in the aged pine bark . Are your blends washed after sieving to remove the unseen fines . With the scoria and pine bark blend i wash everything until the water runs clean usually into the grow beds .

Cheers Alpine

[Luke308]

I think it depends on what type of tree. Eg deciduous or evergreen. I think Deciduous would be okay with any of them, whereas pines would be better off in the 4-6mm. That is my understanding anyway.

[kcpoole]

for me depends on the size of the pot and tree, not the type of tree.
for most of my trees in training pots / plastics, I use 1 - 7 mm ( so voted for the closest brett).
Small Shohin and Mame pots have mix with the 5-7 mm sifted out, so 1 - 4 mm..

Everyting else1 - 7 mm with a larger drainage layer of hard scoria underneath for those in grow pots or boxes/

Ken

[Bretts]

Thanks for the comments and votes
In the other thread on boons soil mix I noticed some think that sifting is only to remove the fine particles/dust. But the most efficient substrate will have a small uniform size.
Roots grow on the surface of soil particles. So the more surface you have the more area there is for the roots to grow. As soil particles become smaller they dramatically increase their efficiency to provide surface area for the roots to grow without taking up as much room.
But at some point we can go too small and water tension will not allow the soil to drain. So how small can we go.
Herb Gustafson tells us it should be between 2.4mm and 3.2mm. I might improve my sifter grades in the future but at the moment I use the 2-4mm size on my best trees in bonsai pots.

Of course this does not stop us using different sizes in larger pots where the tree does not need all that surface area or any other various situations. I still experiment with drainage layers but not when room in the pot is minimal.

But sifting is a very important job in bonsai substrates. Not just to get rid of the dust but to also grade the particle sizes.

[Bretts]

Are your blends washed after sieving to remove the unseen fines . With the scoria and pine bark blend i wash everything until the water runs clean usually into the grow beds .

Cheers Alpine

Hi Alpine
I generally don't wash my substrate but only water well after potting until the water runs clear from the pot. I think I should wash this used soil though especially since it was still a little damp when I sifted and some fines have clung to the particles.
Thanks

[alicevinci]

The main thing is which type of tree it is. A bonsai is confined to small quantity of soil throughout the year on which its existence depends.You will get know about the proper soil through this link : http://plantingarden.com/bonsai-care/so ... asics.html

[Bretts]

Thanks for the link

[Mojo Moyogi]

Hi Brett,
2-6mm looks about right to me for texture/particle size, but I would prefer at least 50% to be sharper rather than the rounded particles shown. Sharp sand, 1/4 minus or granite chips have worked well for me in the past as has the marvelous stuff from Qld starting with D. While size uniformity is a consideration, my biggest concern is that bonsai growing media components don't break down during their working life. Dust to 6mm can cause a lot of problems, as can containers that do not have enough drainage.

Re: Herb Gustaffson, I have a couple of his books and I agree with one or 2 of his methods, the particle size you have quoted sounds too small and from memory his bonsai blends contain regular soil, making them rather un-modern. On the whole I can't remember being impressed by too many of the trees in his books either. Whether that is an accurate reflection of his personal design style, that his books are probably aimed at a novice audience or that the trees in his books are just a sample of a far more impressive collection, I don't know.

Not all bonsai authors are masters of the art, conversely, not all Bonsai Masters are authors.

Cheers,
Mojo

[Bretts]

Hi Mojo,

I am sure 2-6mm works good enough but in my opinion I think that when room is limited going to the smallest (but still well draining) uniform size will give the most efficient soil. Small uniform size equates to free draining and large surface area for roots to grow. It seems to me when you are after the most efficient soil including larger particles will only only waste space. Of course for trees in oversize bonsai pots and especially nursery pots this may not be an issue but for more finished trees in tight pots I think it is an important issue.

This blend was created from seconds soil of all description, I even added some old blue aquarium gravel. I agree that sharp is better than rounded so I can kinda go what you say there but also think this mix will do a great job.
From memory here is a list of what is in this mix.
Akadama
Diatomite
Spongelite
zeolite
crushed terracotta
scoria
crushed granite
charcol
appugulite
river gravel and aquarium gravel
Chinese akadama

The last two are the only ones that I would think are not sharp enough. Even though I would be happy to use the river gravel again, especially on the tougher and less worked trees as I know great nurserymen that use it very effectively. I personally would prefer a sharp grit for the trees in tight pots and/or I work the hardest. Grant has led me to Mini crete which has a multitude of gravels sifted washed and graded and crushed granite is available locally if I have time and inclination to sift myself. So I would only purchase the rounder stuff if I was in a pickle.
The Chinese akadama (round brown/red expanded clay balls) as I think Leong calls it I was never happy with. Although it seemed to do all the right things the roundness just seemed wrong and I have memories of a collected tree that died in it. Leong talks the stuff up and seems to do well with it so I am sure it must work but considering the roundness I am happy to wipe it of my list of good medium products.

I am still considering products that break down to a degree. Firstly I believe that if Bonsai are grown a certain way then the roots will form a structure in the pot quickly and will not be affected by the medium breaking down. Well at least if a portion of the medium breaks down creating a mix of "6mm to dust" in your words. I am also considering that if a portion of the mix is expected to break down over a period of time then this will give more room for the ever increasing roots. I don't expect everyone to agree with me here but considering trees that get that first good start in a new substrate It seems to me that there is little that can go wrong after that has happened no matter how the mix breaks down.

I stated Herb more for the honesty of where I was getting some of my info more so than to give what I was saying wieght. I think your memory of the trees in Herb's books are fairly clear but they are definitely healthy. In my opinion or at least for me I find the chapter on soils in his book The Bonsai workshop, very helpful when considering soil mixes and will go back to it for a reference. In fact I think Herb is very good nurseryman if not a great artist.

I will have to disagree and believe it to be a myth that bonsai containers need alot of drainage holes. I believe and I think the world of natural physics agrees with me that as long as there are no low spots without a drainage hole then more or very large holes will not equal more drainage for the pot. Multiple holes and larger holes will help negate the possibility of them becoming blocked but they will not increase the drainage of a pot to any useful degree. It is possible that more holes will help the pot drain in the first instance but in a very short time (minutes) a pot with a single smaller hole will have equal drainage to a pot with more holes.

I apreciate your thoughtful response
Brett

[Jow]

Just read Peter Teas latest post. It's on soil and is probably the best bit of writing about soils on the net that i have read. Check it out.

http://peterteabonsai.wordpress.com/201 ... g-a-beast/

[Scott Roxburgh]

I missed this when the poll was up but I'd go the 4-6mm on most trees in development. I'd go smaller on Shohin etc. I'd changed the proportions of the items in the mix for deciduous/conifers but I wouldn't use the say a 2-6mm mix though.

After reading then re-reading your posts Brett, I am still unsure of the benefits of the smaller mix on larger trees? Less watering? I have had trees with roots filling the pot, that is, not just on the soil particle surface?

I have always heard that the larger the mix is the stronger the growth, I wonder if this holds? In the link above Peter mentions that it is the dryness that allows the roots to grow?

I do think that a uniform mix within a small particle size band ie 4-6mm or 2-4mm is the way to go.

[Stewart_Toowoomba]

Hey Bretts

Thanks for the survey - as for not many responses compared with views.... members like myself perhaps may not have an 'informed' opinion for this survey at present and to add to the survey may skew the results for those who actually have an valueable opinion to give. I've really enjoyed reading the various postings for your request and inparticular the easy to read review of potting mix from Peter Tea . I was already on his blog feed and felt it worthwhile for nebies and intmediate newbies to read and try to take in. I highly recommend signing up (free) to his posings, as they give a fantastic insight to life and seasons for a professional bonsai nursery from the view of a westerner.

I am still in the throws of going past the local bonsai mix from the big green shed and then adding some diatomite to the mix - now I've read about their ph level and am wondering if i've made the right choice. I have written it all down and try to record my findings and LOOK at my trees.... but time, patience (lack of) and considerations of other variables dictate what i can actually do and the results i get from my trees. My trees are more on danger of me not watering regularly enough or them getting knocked off te shelf from a stray soccer ball than the quality / size of the mix i use...

Thanks for the posting and appreciate all that goes on. We may not respond but it will be read!

Cheers

Stew

[Bretts]

I agree with Colin

http://www.colinlewisbonsai.com/Reading/soils3.html