Best soil for containerized Japanese Maples

M&P
Thank you so much for the comments, they were really helpful. I do have wind problems and with the heat, I'm sure you have more than we do, but it can get bad. I was thinking it would be used with organic material, but the articles I read mostly talked about the product. I'll also check out that bonsai site. I think I have looked at it before. I am with you on the making your own due to cost. I have had good luck with pine bark an organic matter, but it seems to break down a little faster than I like. The addition of the clay might be just the thing.
Kay

 

This is a quite an old thread but I want to get you opinion of a soil mix I'm thinking of using.

It's a combination of Al's gritty mix (http://forums2.gardenweb.com/forums/load/contain/msg1221344425812.html?8314) amended with potting soil. As some of you may already know, Al's gritty mix comprises of equal parts pine bark, Turface, and crushed granite, ie a 1:1:1 mix. This mix is very ideal in drainage, aeration, and water retention. The large particle sizes aide in drainage and aeration while the Turface retains water. The drawback of this mix is that it's highly inorganic; the only organic part being pine bark and that decomposes slowly too. Therefore nutrients are lacking.

That's why I'm thinking of amending Al's gritty mix with potting soil. I'm thinking of equal parts pine bark, Turface, crushed granite, and potting soil, ie a 1:1:1:1 mix. The potting soil should provide the much needed nutrients. I don't want to add too much potting as to inhibit drainage and aeration.

What do you guys think?

 

Squeezied,

I'm also curious to know how any soil medium would affect the gritty mix. I must admit, I've never used the gritty mix before, but went out and bought all of the ingredients earlier today and mixed it all up. I planted 3 small JM's in 2-gallon containers using the mix. I should add that I also included some peat in my gritty mix.

Then I got to thinking... how are my trees going to stay hydrated on 100 degree days this summer? And how much do I want to fiddle around with fertilizers when I water?

So I potted up a couple more, this time incorporating the original soil from the container and mixing that with the gritty mix. Every pot I took a maple out of had tons of earthworms in the soil that I cleaned off of the roots before repotting. You're not going to get any worms with the gritty mix alone. I'm not too sure that the worms will like the new amended soil, either, with all of the grit... but time will tell.

Both mediums I used in repotting the trees today drained very well, and from what I know, that's the most important thing with JM's in a pot. I really liked the feel of the dirt with the gritty mix included in the garden soil/compost. So I suggest you give it a try. I can't imagine the tree dying so soon just because you added some potting mix to the gritty mix. If it doesn't grow well this season, you can try something else next spring :-)

I realize that our climates are very different, so I hope that someone else can chime in soon with some advice.

Regards from Kansas City,
Kevin

 

Squeezied, because you live in a fairly humid climate that gets warm, but not overly hot, I think you can probably get away with little to no organic material - though some organic, in my mind, is always good. Kevin, you probably encounter many of the same challenges as I do with regards to an ideal soil mix - water retentive without being boggy, free-draining without being dry. And then you add in the heat and the wind, ugh.

I've only been using it for a bare year, but so far I - and more importantly, my maples - really like using the felt pots (for those that aren't in the ground or in training for bonsai), the ability for the roots to breathe in summer and not get so hot as they would in the plastic pots. They require a little more protection in winter, but that's a minor trade-off to me. The soil mix I started using at the same time is pretty much equal amounts of Fox Farm Ocean Forest potting soil (has perlite in it, organice, has the mycorrhizae, etc), pine bark mulch, turface and coco coir. I really, really like the coco coir - doesn't break down like the soil and bark will, soaks up and retains water without keeping the mix soggy (gives a bit of a buffer on those hot days), adds bulk, aeration and drainage to the mix... I don't really see any downside with it. A fellow member of our local bonsai club turned me on to it and I am very happy he did.