Repotting JM Babies

[TheBlackBonsai]

Happy Sunday everyone,
I have four little deshojo maple seedlings that I’d like to move to bigger pots to start developing the trunks. Would you all suggest waiting until repotting season to do this or is it possible to repot them safely now? I’ve been researching and have come up with mixed methods. They’re in small 5inch plastic pots at the moment and about 12inches tall. Thank you kindly for your input!

 

[TinyArt]

Someone with knowledge will arrive in a moment...
your avatar kitten!

 

[badatusernames]

At this time in my journey I would be strictly repotting those in spring.

I have heard other things, such as it not being a problem for younger trees (I almost killed a JM sapling last week when a pot fell over so I don't buy that), as well as that there are actually three times in a year you can repot - spring, some mid-summer dormancy, and then in autumn - but... yeah.

No thanks. Spring.

 

[TheBlackBonsai]

Someone with knowledge will arrive in a moment...
your avatar kitten!

Thanks! My little meezer kitten… she runs things

 

[Arlithrien]

What substrate are they in? Up-potting is generally safe to do year-round, however if they're in a coarse mix that doesn't compact, the roots could be disturbed in the process. If they're in peat or similar substrate and the rootball is compacted there shouldnt be an issue surrounding the existing rootball with more substrate.

 

[TheBlackBonsai]

Seems like they’re in basic potting soil with a bark layer on top

 

[Arlithrien]

Seems like they’re in basic potting soil with a bark layer on top

Should be fine imo.

 

[QuantumSparky]

If you could somehow slip pot them into a bigger home then that should be OK, but if it's really loose substrate then see other comments for suggestions :/

 

[n8]

I'd wait. These are spindly and look weak. Not that up-potting requires super strong plants, but you're not going to improve their health or growth by doing it now in the heat of the summer. Wait until fall or spring. LA weather gives your flexibility.

 

[Shibui]

I'd wait. These are spindly and look weak.

It is likely these are weak because they are still in little pots and just can't get a good head of steam up.
Young seedlings can be bare rooted and potted on at any time of year but usually with minimal root pruning but, as mentioned, it is even safer and easier to just pot on into larger pots without disturbing the whole root mass too much. If there's not many roots and the current soil falls off it won't matter. Just gently arrange the roots in the new soil and continue care.
The seedlings may still have enough growing season in CA to make some use of the larger space but I would definitely do a full repot and root trim next spring. Nebari is highly valued on maple bonsai and the best way to get good nebari is to start early.

 

[penumbra]

I do a major job of up potting in summer and late summer every year as I have done for the past 50 years. I think it is a really good time to re-pot JM. I have several I re-potted a couple weeks ago and several seedlings I will re-pot within the next couple weeks.
If the job requires massive root pruning I wait until very early spring. If it does not, the timing is perfect for me. The fresh new soil helps insulate the tender roots when the pots freeze in winter.

 

[Arlithrien]

It is likely these are weak because they are still in little pots and just can't get a good head of steam up.

Leaves look dried and warped, perhaps too much sun/wind exposure?

I have maples of similar age and they are healthy in their small pots. But I agree, pot size (and genetics) can make a huge difference in growth. All three trees pictured are 2 years old and only the middle has begun its 2nd flush of growth.

 

[Deep Sea Diver]

Yep, go for it. I’ve done multiple up pots of young maples up through August out here. Did two last week.

As Bill V says, the key is the aftercare. It takes time for each tree to get settled in the media

I keep mine in dappled shade out of the wind for a month or more afterwards

Cheers
DSD sends

 

[LanceMac10]

Where/what do you gain?

 

[TheBlackBonsai]

I really appreciate everyone’s feedback. It’s great to see the differing options.

While they are a little weak looking I’ve decided to repot them and see how it goes. I’m building a little Maple shade area for them as I’ve realized that possibility the shade I’ve been providing them under my elm tree in my backyard is not enough. Fingers Crossed. Im hoping their new homes give them space to stretch their feet and bounce back a little before spring. Thank you everyone for clearing this up I’ll check back in a few weeks with an update to let you all know how it went.
Thanks!!