JR_Roosa

Hey, another Denverite! Hello!

I just did what you're thinking of, and I thought I'd put up what I did for you to think about and for other people to criticize. ;) BTW, I'm more-or-less a beginner, and I really wouldn't jump in and repeat what I did until a bunch of other people have something to say about it.

After two seasons of really disappointing growth for many of my trees, I decided that this season I am going to go for bigger, healthier trees in more reasonable pots and more reasonable soil. I tried two varieties of retail bonsai soil that I didn't like very much last year and the year before. One (comes in a white bag) was mostly sand, and I found that it dried out fairly quickly, didn't drain well, turned the root balls into bricks, and the trees (junipers, maple) didn't like it much. I also tried the mix from the Bonsai nursery on Federal, and that was nice and granular, but it's pricey, and I found that it was really difficult for me to keep watered, especially during our hot summer last year (I don't have an automatic watering system). I wanted something that drained well, stayed moist all day or for two days in our dry summers, and didn't cost $5 a quart.

This year, I got soil sieves (3mm, 5mm, 7mm) and made my own mix and repotted a couple of trees this weekend. If they do well, everybody else will get a new pot and new dirt this season too. I know you said you don't want to make your own, but the only stuff I could find around here is very expensive compared to $10 sieves and 30 minutes of sifting bulk components. Plus, I feel that if I make my own, I can watch how the trees respond and vary the mix as needed in the future. If you are set against making your own, I would go check out the mix from the nursery on Ferderal and see what you think.

My mix is 60:40::drainage:organic. Everything is sifted, and I made a bucket of 3-5mm mix for smaller pots and another of 5-7mm mix for bigger pots. I don't know if that's really rational, but there it is.

The 40% organic component is fine fir bark (sold as fine orchid bark, but I found 3cu ft bags of pretty much the same stuff at the nursery for $6).

For drainage, I used 20% pea gravel (mainly for weight, very cheap at the nursery), 10% red lava (it's more expensive, and I only used it because it was on hand, but I probalby won't use it next time unless i can find big bags of it), and 30% Kanuma (weird yellow Japanese volcanic clay, popular for azaleas). The Kanuma was a bit of an impulse buy from the Tagawa nursery on Parker Rd ($25 for ~3cu ft). The healthiest tree I have is in a mix with some Kanuma, and I was really impressed at how that stuff and Akadama soaks up water and stays moist for a long time. You may prefer something else entirely, but I thought I'd give it a shot. Oh, and I really hate the look of perlite floating to the top of the pot when I water, so I suppose if I wasn't so biased, I use that instead of fancy Japanese dirt.

The mixes look really weird, but I am shocked at how long they have stayed moist. I thought that with all the air space, I'd be fighting to keep them from drying out, but not so. We'll see how they do.

I used shallow terra-cotta bulb pots rather than gallon nursery cans since I don't want to fight with deep roots later on in getting trees into proper bonsai pots.

I have no suggestions for sophisticated fertilizer, I use regular miracle grow, and miracid for my azalea and maple. I don't think it kills trees outright, but I also can't say that it wasn't causing my disappointing problems last year.

Anyway, I hope that gives you some ideas. I'm sure that the commentary that follows will probably be more helpful than what I've written.

-J.