What kind of tree? You may want to tease out that rootball now and fix bad roots before they grow into bigger issues. Point being, this may reduce the root ball considerably and require a smaller root bag. no basis for this, but maybe 20% bigger than the trimmed down rootball? The telperion guys only ever use 12-14" bags no matter what. On one stream ryan says the trunk on a tree from them was as thick as the 12" rootbag. Wild!
What I do is to cut a piece of 1/4 in plywood in a size to fit half way down the pond baskets. I use the hard clay hydroponic clay balls to fill the bottom half of the basket, put the plywood square down on top of the balls, then put a layer of bonsai soil, then the tree base, and then fill with more soil.
I get nice flat radial roots and the trees love the aeration their roots get from the air holes, plus it’s self root pruning.
Thanks for this awesome bit of knowledge! Can’t wait to try this out. I was about plant some trees this weekend but the area I picked out gets too much sun for my liking. Summers in Utah are getting ridiculous.
I hope the technique works as well for you as it has for me.
Sorry for the delay in answering this, and it’s too late to add another two cents for this year, but… I had the same question myself, and this summer began experimenting with using only the bottom half of the basket (4-5 inches) and not planting it so deep. It’s easy to cut the baskets down and make them more shallow. I like the way that they pretty much self root-prune in those - and again, I like the price!
I’d like to try this technique. Nine or ten years seems like a long time to wait, though. Is there any way of speeding up growth?
From what I hear putting them in the ground for 2-3 years is like a ten year jump. In growth. But I wonder the same thing.
Man this is really helpful! I think I’m going to try this method for sure. What did you fill the basket with? Did you do a full transplant getting rid of the nursery soil completely? I was thinking of using the same soil just slip potting into the basket.
Depends on where you are and if you are growing from one year old seedling or something further along. I hear growing in the PNW is like 3x the growth speed of growing on the east coast. Also, fertilize.
This is a fantastic post with a lot of good information. I have a chunky corticosa elm I received from Mark Comstock in 2016. Its been in the ground since then and has grown to about 7’ The trunk and base are about the thickness desired and are probably ready for step 2 in a grow box. I also have two Amur maples that are ready to get dug. In your experience, when is the best time to trunk chop and then dig/move to grow box. I have done this in the spring as buds swell with mixed results, however when I did this on two zelkova two years back they didn’t survive. This may have been due to wonky spring weather in St. Louis.
One major advantage i can see is that when you dig them up that pot is instantly going to act like an air pot and start air pruning the roots. I’m planning to experiment with air potting in spring with some of these:
plus some normal terracota pots that i’ve drilled lots of small holes into to see what effect they have on growth and root development. Look forward to seeing how your trees develop (the pictures you’ve posted look like great little trees!!!)
What on earth are these? They look like they are constructed from building drainage materials. Were these constructed or purchased? Maybe sump pump basins?
Hahahaha! Originally it was a company called AirPots that came up with this design although lots of cheaper versions are available now. I got a pack of 10 off amazon (7ltr) for £25. They come ‘flat pack’ but essentially you just roll each one up with the base in place and pop a little plug (blue bit on side of pot above) to keep it in place
Ok…Good repurposing of very specialized geotechnical product!
I like the idea. The fabric pots tend to tear, and I suspect will be difficult to extract the tree if fine roots penetrate the fabric. Look forward to seeing what your results are with these.
What will you place in them and what soil will you use?
I dont have enough land to grow anything in the ground so using these purely for nursery stock initial growing prior to going into a bonsai training pot. I’m planning to use my conifer soil mix of akadama, shredded pine bark and pumice in a 2:2:1 ratio. I use the pine bark because it holds a little more moisture and with my job i struggle to water more than twice/day which isnt always enough in the really hot summer periods (even in the UK!!!)
Same here on land limits. Neighborhood setting, and already too many big trees so I have to be able to move things throughout the season.
I might just give them a try. Oddly enough, pine bark is something we struggle to find here…as fir bark is so prevalent that pine is not imported across the mountains. I wonder if pine is better than fir bark…
I have about 60 shimpaku that were in 1 gallon nursery pots. i put about 5 in the ground above a tile with 1/8 in aged pine bark and about 40 percent 1/8 gravel, above ceramic tile. 1 photo is 2 years in the ground next to 2 years in 3 gal nursery pot cut down shallower. 2nd photo is i grow bags but i just did that this year. 3rd photo is the Nebari of the 2 year ground planted. After seeing the results i put 25 more in the ground. i used plastic squares cut from the plastic trunk protectors you find at hardware stores. After this i put 5 in pond baskets with pumice, pine bark, and lava. time will tell. ill post results as they come in.
Lovely plants Peter! Very envious indeed!!! I’ll do like wise with any results i get (or don’t)
I’ve found fine pine bark pretty hard to get hold of in the UK too, plenty of the coarse stuff but not much fine. And pretty pricey too!! It cant hurt to give them a try. You can cut them down to whatever height you need and they are supposed to create a dense and fine root network, exactly what is supposed to be desired in bonsai so