Im really curious what you guys use as a water retaining part of your potting mix.

I heard about pine bark, but I can't imagine that as I only get these 70L bags of pine bark which are 6-8 cms particles.

I repotted a ficus as it really needed. I used akadama as a part of the mixture. It seems it breaks really easy(Im new to akadama) So Im not sure it will be fine for me for the outdoor trees as we have these winters that one day its -5 degrees and then its +10 degrees the next day. It will break down quickly I guess. Because of this Im planning to use cat litter, perlite and zeolite. But I think Im going to need some other ingredient that retains some water. Any tips?

I read somewhere on this site that I should mix lava rock akadama and regular potting mix. Won't the regular potting mix clog the mix? It makes no sense to me to have some aeriation and then fill them with dirt.

Straight-up kittydama is pretty much perfect for most species. I don't add any other materials, organic or otherwise, to it.

How big are the paricles? Can you buy different particle sizes? If not do you use it from mame to biggest trees as well?

Akadama is by far the best medium. It lasts for years and is inert.

Madartej21 wrote: (1)How big are the paricles? (2)Can you buy different particle sizes? (3)If not do you use it from mame to biggest trees as well?

1.About 2-5mm
2.I don't think so
3.I only have Mame and Shohin really, but they work great for them.

m5eaygeoff wrote: Akadama is by far the best medium. It lasts for years and is inert.

That's very much up to debate, it's hard to say what the best medium is and if there even is one that is superior to all others. I thought Akadama broke down really quickly. It definitely doesn't last a long as diatomaceous earth, which is also inert.

m5eaygeoff wrote: Akadama is by far the best medium. It lasts for years and is inert.

Sure, and that's why I never, absolutely never again will put a juniper in Akadama.

Yeah I think it won't be suitable for me as well.
But the thing bugs me that the other possibilities I mentioned are hard to acquire and hardly or can't select particle size. Oh yeah and the look of it.

You can, sort of, choose the grain size. There are many different sources of kittydama that are used for different purposes, so maybe the diatomaceous earth used to clean up oil is a larger grain size than cat litter.

As for how it looks, I don't think it's that bad



(That's one of Harry Harrington's mountain maples)

You are right. It looks good actually. I will experiment with these. Thanks for the tips

My trees are thriving with the kittydama in my mix, though I've used pine bark in the past with success. Good moisture retention. Breaks down over time, but not as bad as akadama. For particle size, I made (2) sifting pans from perforated sheet metal. You can buy them as well if you've got the coin. 2-6mm goes into my pots, and the rest goes in the garden. Shifting can be long & tedious, but it has been a part of my repotting ritual since I started, and I look forward to it every late winter.

As far as useful material in a bag (i.e. bang for your buck):
~2/3 useful from a large bag of diatomaceous earth (NAPA #8822 in the states, better than litter).
~3/4 useful from fired clay (Turface).
~1/3-1/2 useful from a large bag of pine bark soil conditioner (don't use much anymore)
Still trying to source some good lava rock without spending a fortune.
I don't use pumice as it floats off the top & the color doesn't agree with me.