In-ground Grow Bags

Inspired by the Telperion podcast, I was wondering if anyone knew what type of grow bags they use?

Are they the felt-type ones? They sound like they weren’t the biodegradable type.



Excellent. Thanks :slight_smile:

You’re welcome. Telperion uses a barrier to develop the nebari once they put them in the root control bags.
I use clay pot saucers or ups-a-daisy, or if planting in a big fabric pot, i use a big wide-based bowl put it upside down in the fabric pot, put potting soil-pumice-fine gravel (2:1:1) around the pot, then spread the roots on top of the pot and use g&b bonsai mix-pumice-gravel (1:1:1) to fill the top.

Some are in cedar raised beds.

Yeah I have a raised cedar bed completely unused right now. I was planning on field growing (yard growing?) some of my smaller trees starting next spring anyway. After that podcast I was thinking I should try those grow bags to help keep the roots in check. They sound worth it.

One followup question, instead of the spring do you think I could plant them now? I live in the PNW and theoretically (at least according to the local nurseries) I should be able to plant anything into the ground nearly any time of the year. But I’m thinking that might not be true if I’m pruning the roots in any way.

You’re correct. If you will be working on the roots, you might have to wait till spring next year.
Is this a deciduous? If so, you might be able to work on the roots before putting in a grow bag, and put on a heat mat. Protect your tree from night til mid morning sun for at least a couple of weeks. Don’t wait too long before the first frost kicks in. I live in maple valley,wa.
What i did on a maple last fall (early october) was cross cut the root ball perpendicular to the trunk, worked on the large roots directly under my target nebari spread them on an ups-a-daisy and planted in a fabric pot. Kept it on a “trolley” so i can move it in and out of the garage depending on the weather. I keep it on the heat mat regardless (just unplug when moving out) and i dont put it out under the rain too.

Got good results out of it.

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Yeah mostly deciduous (maybe one redwood). Thanks for the insight. I think I have a plan for the near future.

Unsolicited suggestion on redwood if still in development…
Sort of similar approach, try putting the fabric pot on a plastic pot saucer/holder about twice the size of the pot. Then fill with gravel and water. Like growing corns in a fabric shopping bag.
Experiment on a different redwood first. I did this on my bald cypress, dawn redwoods and mimosa

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A little off topic, apologies, in the same podcast am I right that they said to get a field grown JBP to back bud on the trunk, to allow a long and strong leader to grow and once its hardened off stripp the needles off the sacrificial leader except for the very apical whirl?

They leave the current year’s needles on at the apex.
Needle work in June (northern hemisphere/pnw).
Prune in September.
Auxin is produced at the tips and travels down tk the roots.
Cytokinin is produced by th roots and passively travels tk the tips.
By plucking needles except for the current year’s needles at the tip of the sacrifice branch, the pine loses it’s sugar factory, the pine produces more buds so it could produce more needles to produce more sugar to balance the the auxin-cytokinin-carbohydrate combo.
Hypothetically, since the sacrifice leader is long and only has needles at the tip, plant generates buds closer the the base/colar of the leader (fail-safe uf the leader dies) and builds up through the length of the branch. Provided there is equal amounts of auxin and cytokinin.
Think these hormones as our insulin and cortisol.


Great clarification ThienXiang thanks.

You’re welcome. This is to the best of my understanding - finding what’s similar to human physiology.

I too can attest to the quality of the Rootmaker products. Used a series of them (small, medium and large pots, as well as bags) for the first 10 years when starting 60 bonsai from seedlings back in 2008. Develops great root systems. Check out their website.


I wonder if the guys at Telperion are sifting out the fine particles when they are planting the trees into the grow bags?

I don’t think they have to. They use more organic materials. It is safe to assume that they would take the big pieces (twigs, wood, rocks, etc.)

As far as I understand, they are using 40% pumice.

How do you know telperion uses this brand?

Someone asked them and shared the information on another thread.

Actually, Telperion uses the pots from not their grow bags.

These are the in-ground grow bags they use -

I contacted Telperion farms directly and that is the information they gave.

I’ve used Rootmaker pots for years - they’re awesome. Assume the grow bags are of equal high quality for what they try to achieve.