When to pot up 10 mo. old japanese maple seedlings

[bpancakes]

I couldnt find a thread talking about this and I am finding conflicting information on whether I should wait until they are leafed out vs bud break vs bud swell?! Feeling pretty confident in my ability to seperate them now. They are currently 5-9 inches tall in a single flat looking pretty happy and just starting bud swelling I believe in western washington zone 8. I also have some acer circinatum air layers I collected last summer in pots Im thinking of planting into the ground, would I approach both of these in the same time of year? Thanks for your help!

 

[Piedmont Bonsai]

You can pot them up now.

At this stage I would recommend removing as much of the taproot as you feel comfortable with to encourage lateral root growth and plant in 2-2.5 inch pots with well draining soil.

By mid summer they should have filled up the small pots and you can scale them up to slightly larger pots like 3.5-4 inch. This is the method I use and I have seen good results

 

[bpancakes]

You can pot them up now.

At this stage I would recommend removing as much of the taproot as you feel comfortable with to encourage lateral root growth and plant in 2-2.5 inch pots with well draining soil.

By mid summer they should have filled up the small pots and you can scale them up to slightly larger pots like 3.5-4 inch. This is the method I use and I have seen good results

I really appreciate the response, great advice thank you! I'm on it! Very exciting

 

[Shibui]

A great time to transplant any maple.
I'd also encourage you to chop the roots to discourage down growth and promote more lateral root growth.
I'd usually transplant most seedlings into 4" pots to give a bit extra space to grow rather than trying to pot up through the growing season or into flats of some sort but lots of different ways will also work.
Should be a good time to transfer layers to the grow beds too. They should already have a great lateral spread of roots so may not need much/any root trimming.

The germinating seedlings in your other pic are about the stage I often prick out into individual pots. At that age they hardly even notice most of the root being cut. Seedlings can also be left in the tray through the first summer, as you did last year, but often growth is reduced because they all compete for the same nutrients, light and water. The trees I transplant to individual pots inevitably grow more than the same seedlings in shared containers.

 

[bpancakes]

A great time to transplant any maple.
I'd also encourage you to chop the roots to discourage down growth and promote more lateral root growth.
I'd usually transplant most seedlings into 4" pots to give a bit extra space to grow rather than trying to pot up through the growing season or into flats of some sort but lots of different ways will also work.
Should be a good time to transfer layers to the grow beds too. They should already have a great lateral spread of roots so may not need much/any root trimming.

The germinating seedlings in your other pic are about the stage I often prick out into individual pots. At that age they hardly even notice most of the root being cut. Seedlings can also be left in the tray through the first summer, as you did last year, but often growth is reduced because they all compete for the same nutrients, light and water. The trees I transplant to individual pots inevitably grow more than the same seedlings in shared containers.

I really appreciate the sharing of seeds of knowledge. All of that was helpful. So much useful info, it makes me very excited to go forward!!

 

[penumbra]

I don't have any idea how many seedlings you have or the number of sources, but you likely to see a bit a variance in the vigor and size of them. Consider this as you up-pot them. I potted up about 80 last years and have about 150 this year. They are not equal at all based upon their varied genetics and such. Some last year, and some this year will go straight to gallon pots and others in pots as small as 4 inches. Root pruning will also be according to individual plants. Some will have rather small root systems, and others will have more complex root development. Last years re-potted plants were from several sources so obviously they have a larger genetic pool, but even those from a single tree started last year have a bit of variation. Because all hybrid Japanese maples have a mix of genetics, this variance is to be expected. Look for it as sometimes there are real treasures. In your climate you need to do this soon, but consider too that seedling plants, even in full leaf, will transplant well. I just prefer to do the re-potting when buds are swelling.

 

[bpancakes]

I don't have any idea how many seedlings you have or the number of sources, but you likely to see a bit a variance in the vigor and size of them. Consider this as you up-pot them. I potted up about 80 last years and have about 150 this year. They are not equal at all based upon their varied genetics and such. Some last year, and some this year will go straight to gallon pots and others in pots as small as 4 inches. Root pruning will also be according to individual plants. Some will have rather small root systems, and others will have more complex root development. Last years re-potted plants were from several sources so obviously they have a larger genetic pool, but even those from a single tree started last year have a bit of variation. Because all hybrid Japanese maples have a mix of genetics, this variance is to be expected. Look for it as sometimes there are real treasures. In your climate you need to do this soon, but consider too that seedling plants, even in full leaf, will transplant well. I just prefer to do the re-potting when buds are swelling.

I really appreciate your response this is all great advice. I had 2 dozen last year and looking at them now I see a ton of variance which I enjoy. I potted up all of those and found another 100 in some gravel and leaves next to the parent trees. They seemingly loved the shade next to the building and the gravel/leaf mix, tons of seedlings. 5 feet away in the direct sun with the same medium yielded very few to none. I pruned half the saplings and left the other half as is as a test of my skill and timing. Such a happy and exciting time of the year for me finding these beautiful little trees. Im glad to grab them, the property owner will be burning everything on the gravel with a torch any day now. The mix I'm using seems to work ok in general, mostly perlite and then a split between compost and mushroom compost for the rest. Probably far too much organics but it drains well