What is tha difference between growing n a colander vs growing in the ground?

I like the idea of growing in a colander. It would certainly make root pruning much easier. But will you get the same amount of growth in a colander as you would planting it in the ground? And it was my thought that route pruning limited growth. So, if you’re looking to grow a large trunk, would growing in a colander do just as well?


Wow! I really need to edit my writing. But I think you get the message.

Depends on the size of the colander I guess. Some of those giant colanders might effectively get the same results as planting them in the ground.

But generically speaking, a tree in the ground will probably grow a thicker trunk in the same period of time as it will have more area for the roots to grow. It’ll move more resources with more roots and more foliage and get thicker faster. But eventually you’ll have to pull it out of the ground and reduce the root mass by quite a bit. The colander method helps keep the roots somewhat in check while allowing them more room to grow than the typical bonsai pot. The trunks will thicken faster than in a bonsai pot but slower than in the ground.


Nothing is as fast as growing in the ground.

Grow pots are theoretically another way to develop trees prior to a final bonsai pot selection, but don’t expect the same results as a well-tended grow bed. For some of us, grow boxes and pots are the only option.

Colanders are for pine root development because of the aeration. The roots react to the air and instead of circling the edge of the pot, they ramify backwards and build the feeders that are required for healthy life in a bonsai pot. Colanders do absolutely nothing special beyond draining well for other trees. They also look like shit and break easy, so there is no need to use them on a Japanese Maple. The roots will grow right out the bottom and sides.

Now that I think about it, I got one Doug Fir yamadori from Cho Bonsai in a colander a few years back. That might be another species that benefits from a colander. I am not sure. It didn’t hang around long in it.

I also prefer koi pond baskets to colanders for my pines.



Great information guys. Thank you so much. So much to learn.

Thank you for that answer Nicholas. Appreciate the response.

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They’re not “only for pines” if you grow most any deciduous tree in a colander you will indeed get a denser more ramified, more effective root system. In a much shorter amount of time. Instead of long roots circling the pot. When root tips start to grow out of the holes of the colanders or pond baskets with my trees I just rob them off with my finger. I have gotten extremely dense ramified root systems on maples in no time in colanders.


That’s cool, Mike.

What pro do you know who also grows deciduous trees in colanders? I said that it drains well, which is a perk, but only pine roots react to air and ramify backwards. All that you are doing is essentially the same for mame or small shohin to develop roots. You double pot and continually cut the roots out of the drain holes. It does indeed build up the rootball but it can happen in anything not just your aunt Ida’s old spaghetti strainer.

The unique and most beneficial use of a colander is with pines.

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@Joe_Perry How about the Mirai stream on repotting pomegranate? The pomegranate was potted into a colander after being dug from the growing bed, and look how dense that rootball is.

I am sure you just heard someone tell you that colanders only ramified pine roots and now you travel from forum to forum just repeating this information. Instead of trying things out and speaking from experience. No need to be a condescending prick Joe.

If you’re putting lava in your deciduous mix and then putting them in colanders, you’re doing it wrong. You can’t expect to use the same soil for pines as for deciduous in a colander. I use almost 100% DE. My results speak for themselves and I know plenty of people that grow deciduous in colanders.


Boom! Lol as he drops the mic and struts off stage. Tell us how you really feel, Mike!

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And furthermore, how many pros grow deciduous stock and develop deciduous material at the early stages? Not that many. Because it doesn’t suit their business model, understandably, when they can purchase already grown trunks to throw into the development stage and make a faster turn around for their investment. I don’t keep deciduous trees in the refinement stage in colanders, only when I’m growing them in the development stage.

When I was brash and full of myself like you are, I had an Azalea in a colander. Adair Martin set me straight on the specific benefits of colanders. I trust him more than you and even more than a single Mirai stream. As I said before, colanders drain well, but the most beneficial and unique use is with pines and only pines. You can achieve the same results on a deciduous tree with a grow box. What you are experiencing is just embarrassment, which is understandable. I would be happy to discuss it with you further in Rochester at the Nationals in a few months. I am interested to see if you are so cavalier about things when we meet in person. :kissing_heart:

Well! That was fun😨. Thank you both for the input. Hope no feelings were hurt. It seems you guys are familiar with one another. I, on the other hand, have no idea who people are (yet) or how experienced. 1st year for me. So, when people ask me what I do for fun I say “killing trees”. But allow me to alter the topic. I understand that growing trees in the field is the fastest way to get growth but, would large containers, say around 24-30 inch terra cotta, have the same results? I’m developing several plants this way. Hmmmm🤔, perhaps I should try a colander in a large pot?


No worries! Always good to hear other ideas when presented well. I certainly don’t know it all, but when someone like Adair takes me to school on my practices, I listen.

Here’s a big grow pot I made for my Quercus suber. Cost me $6 in scrap wood.


Or, you can use this, your choice.

A colander won’t hurt your tree! They drain well as I keep saying, but, you will get the same results with roots on deciduous material in a big grow pot.

As to your question, no matter how many holes your colander has, or how big your grow boxes are, your trees will never be as fast to thicken as if they were in the ground.


No we’re not familiar with each other, but I am familiar with bonsai snobbery, and this is it at it’s finest. I was talked down to for sharing my legitimate experience in using colanders by someone who was told something by someone and now it’s as good as gospel. Same old same old. Some people just don’t want to have an open conversation about technique or an exchange of ideas, because they’re just plain right and how could anything else also be right. So they have to talk down to people, minimize them, to make themselves feel superior. Bonsai elitism.

Listen, no matter what me or joe say, just recognize that in bonsai the only way you will know something works is to try it out, experiment with different soils, growboxes, etc. find out for yourself. It’s better than just repeating something somebody told you.

Side note, I also use wooden grow boxes that I build. But I prefer to grow a lot of deciduousn in colanders for a couple years before I repot into a grow box to jump start root ramification and density.

Well, there you go, Sailor!

Bonsai online usually boils down to headbutts and grunting.

It’s important to note that neither me or my new buddy, Mike, are trying to give you advice that will hurt your tree. I like Koi baskets for pines. That’s what I was taught by someone at a high level. Do what you will and find out what works for you.

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Thanks again. I guess it’s a trade off though. Faster growth or radial ramification. One would think you have more control if grown in a container or colander. Not sure if the trade off would be that significant. I assume the larger plants that one can buy at a nursery are container grown. I think I actually will try the colander in a large container. And maybe sometime down the line I can get a couple of seedlings and grow each in a different way to try and see what works best. Again, I really appreciate the feedback. I’m new to Mirai but love it already.

Give it a shot! Sounds like you have a plan!

  1. Adair doesn’t know everything :slight_smile: (yes, I know Adair personally).

  2. How about trying this one on for size: what about planting a tree in a colander, then planting that colander into a larger colander or (gasp!) the ground? Certain people will yell and scream that it defeats the purpose of using a colander (automatic root pruning and ramification) and that it’s pointless. Others (who have done it) claim that if you start a tree in a colander, develop a ramified root system, then plant it in the ground…you will maintain the dense ramified root system and also allow escaping roots to develop. Which allows faster growth/development of the tree.

I’ve never tried it but it seems like it could work. Yet many will shout down any attempt at discussion of such an approach.