Randy Knight follow up Question and Answer on sawdust healing bed

I know Randy through one degree of separation and he was kind enough to answer a question I sent him. I want everyone at Mirai to benefit from his wisdom so here is our brief Q&A.

First off, I can’t thank you enough for your stream today. Sooo much information. I’ve been having low success rate collecting my field grown trees. I think due to clay soil and lack of capillary roots so I want to do the sawdust bed method. My field is in Pennsylvania at my parent’s property so completely different back on the east coast and I bring the trees to my home in Colorado. I know, I should just be collecting in Colorado but I love growing in the field.

I want the higher success rate but I fear the cold and wind of Colorado. I live in Golden Colorado on the front range. Winds can be brutal especially in the winter and spring. Would it be an issue to have trees exposed all winter without protection in the sawdust bed? I’m thinking red japanese maples and other non native species could have considerable die back or may just plain die if exposed to Colorado winter. Might it be good to plant the tree in a porous container filled with sawdust, which is then heeled into a sawdust bed? Then when the winter freeze comes this would enable me to pull it out of the bed and into a winter protection such as a garage or cold frame structure?

Maybe this type of solution would be good? I’m just thinking out loud and would greatly appreciate any thoughts you have on this.


Hi Eric.

Thanks for the kind words.

Yes the winter/winds will kill the Japanese maples for sure. Your environment is tough on non native deciduous as you know.

Spring sun on the south side of the deciduous trunks can be damaging as well. Warm spring sun gets the juices flowing in the cambium on the sun exposed side first. Then overnight freezes kill the bark.

Summer wind will also be a potential problem. Think about some type of wind break. The issue will always be dessication.

Your idea of a porous container in the sawdust bed could work. Anderson flat or similar probably would work best. Colander will not work nearly as well. Not enough close ground contact I don’t think.

Whatever you use, make sure it rests directly on the ground. Ideally with landscape fabric in place first. Prevents roots from growing into the earth as easily.

I completely understand about field growing. Hope some of this helps.

Great info, thank you for investing the time and feedback. I will heel in my field collected plants on the north side of my house in containers, within a bed, with a windbreak. In winter, the deciduous will come into the garage. The hardy conifers could probably stay outside provided the wind break is sufficient, right? Or would you bring them in from a Colorado winter too?

For the first time I noticed another bonsai professional I know who planted a collected tree in what appears to be 100% sawdust as well. I’m excited to try this method (as I sit here and watch a 10 year old scots pine dying and brittle from a poor collection from the field).

Hardy conifers should be ok outside with wind protection.
Larry Jackal puts his trees in holes in the ground over winter.

Thanks again. I’m REALLY looking forward to your next Mirai stream. I hope to buy some trees off of you when I get up your way and start studying with Ryan.

You’re welcome.


Thanks for sharing, good luck.

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That was a great stream with Randy. Even though I’m in a very different part of the world I think I got more than a few nuggets. The saw dust/wood chip thing is very interesting.

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@PutItInTheGround – Do you think the sawdust healing method will work well on junipers? I saw the livestream with Randy and the photos of his sawdust beds all show pines, whereas when they show junipers on that stream, they are in the pumice containers.

I’ve put a couple junipers into sawdust, but I am noticing that even watering only once a day in Colorado, the sawdust seems to stay moist underneath the top layer, and I’m wondering if that is too wet for junipers, or how to properly calibrate the watering for these collected trees.

Thank you!

Bonsai Floral Gardens in British Columbia puts their junipers in sawdust beds.
I believe this method should work on a wide variety of species, if not all of them.

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Thanks for sharing.

Have you seen Harry Harringtons method of aftercare for old collected hawthorns? Among other things, he uses a black plastic bag to maintain humidity, wonder if it could help protect from winds in your case?

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Thanks, appreciate that bit of knowledge!!!

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