JM seed can require both a warm stratification and a cold stratification.

Not really.

2-3 months stratification is enough for the plain maple species and most A. p. cultivars, as well as for A. buergerianum..

A. japonicum, A. shirasawanum, and other species that live in colder, mountainous climate need 2-3 months warm stratif., then 2-3 months cold stratif.

The quality of the seeds is essential : when gathered too early, or too late, they won't be viable. Timing is an important factor when you collect seeds.

Also, the soil must be disease-, or fungus-free. That's why I always add some crushed charcoal to my mx, and a pinch of Bordeaux mix.

With seeds from a reliable provider, it always work.

With collected seeds, it's very uncertain...

PS : either Leo edited his post while I was typing my reply, or I read too quicly : I totally agree with what he wrote in his post after reading it more carefully...
 
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Any ideas on when i can pot these up into larger containers? I assume i need to be very careful with while they are in leaf?
 
Any ideas on when i can pot these up into larger containers? I assume i need to be very careful with while they are in leaf?

Hi RobertB,
Try slip potting these into 3 litre(1 gallon) without touching roots - eg lift carefully out of plug ( when plug shows roots through to the bottom) and pot into new pot. I wouldn’t worry about nebari this year as you need strong roots to start, then after either 1-2 years depends on climate have a look at little trunk and roots etc ( cutting off bottom growing roots etc. Don’t be a hurry tho lol.
Hope that helps,
Charles
 
Try slip potting these into 3 litre(1 gallon)

Isn't that a bit too much for 2-3 mm seedlings ?...

I'd pot them into 9 cm pots (about half an inch and two toes)

But OK, I live in a "small country", :D

Seriously, 3-litre pots after one year, you're joking, aren't you.

Or you must be confused between litres, pints, ounces, kilogrammes, Dutch-German-Polish units of measurements from the 17th century (https://en.wikipedia.org/wiki/Daniel_Gabriel_Fahrenheit) :oops:
 
I guess I was more thinking like minimum pairs of leaves before planting out. Or should I just wait till spring 2019. That was my base plan but the seed soil is difficult to keep watered properly. I have had a few die off.
 
Isn't that a bit too much for 2-3 mm seedlings ?...

I'd pot them into 9 cm pots (about half an inch and two toes)

But OK, I live in a "small country", :D

Seriously, 3-litre pots after one year, you're joking, aren't you.

Or you must be confused between litres, pints, ounces, kilogrammes, Dutch-German-Polish units of measurements from the 17th century (https://en.wikipedia.org/wiki/Daniel_Gabriel_Fahrenheit) :oops:

Hi AlainK,
So yes at 2-3 mm seedlings a 3 litre pot would be tooooo big, but after OP gets a bit of Spring growth , say 6 months and 8-15 leaves there won’t be a problem. If watering be a problem with small plug then I agree with you about a 9 cm pot first ( given that a 9 cm pot is only 100 mls off 1 litre anyway :-).
Wasn’t joking “no” but was expecting the babies would grow a few more leaves and roots to fill out plug etc.
Also I might have guessed wrong but the plugs that are shown in the photos look like about 5cm plug.
Well, maybe optimistic but after 1-2 years they would be slip potted into a 5 litre size for max growth etc.
Not trying to pick a fight but hey a year is a long time for a seedling, isn’t it?
Charles

p.s metric here in NZ.
 
I guess I was more thinking like minimum pairs of leaves before planting out. Or should I just wait till spring 2019. That was my base plan but the seed soil is difficult to keep watered properly. I have had a few die off.

Hi RobertB,
If you have to move them on because of watering, then @AlainK has good thinking of small 7-9 cm pot for a year or two.
I think you need to look after these babies in potting mix, until they look like “whips” after a 1-2 years then look at the planting out thing.
You have done fantastic with the seed germination, just don’t be in a hurry, as if you planted out the babies they could all get burnt off in the heat of summer.
Hope that helps,
Charles
 
Hi RobertB,
If you have to move them on because of watering, then @AlainK has good thinking of small 7-9 cm pot for a year or two.
I think you need to look after these babies in potting mix, until they look like “whips” after a 1-2 years then look at the planting out thing.
You have done fantastic with the seed germination, just don’t be in a hurry, as if you planted out the babies they could all get burnt off in the heat of summer.
Hope that helps,
Charles

Charles, thank you for the advice. I planted one out two weeks ago as a test in a 3x3 container. It's slowly getting used to its new container.

I just had a some problems with damping off at first. It seems like some of the seedlings just were not strong enough either. For the past month they have been sitting about the same. No more dead! They are starting their second pair of leaves now. Some are already up.

Also, I do not recommend sand as a top dressing for Japanese maple seedlings. Mine seam to hate it! The ones planted in bonsai mix with sand top coat have struggled and most have died.

Next year I will do more but start whole batch in large plastic container. I tried this also this year and these seedlings are growing perfect. They already are growing second leaves and they were planted almost a month after this other batch that I have shown in earlier threads.
 
Charles, thank you for the advice. I planted one out two weeks ago as a test in a 3x3 container. It's slowly getting used to its new container.

I just had a some problems with damping off at first. It seems like some of the seedlings just were not strong enough either. For the past month they have been sitting about the same. No more dead! They are starting their second pair of leaves now. Some are already up.

Also, I do not recommend sand as a top dressing for Japanese maple seedlings. Mine seam to hate it! The ones planted in bonsai mix with sand top coat have struggled and most have died.

Next year I will do more but start whole batch in large plastic container. I tried this also this year and these seedlings are growing perfect. They already are growing second leaves and they were planted almost a month after this other batch that I have shown in earlier threads.

Hi RobertB,
So I can’t have taken much notice as per the size of these babies. Just growing their first true leaves.
Probably I meant to say, if I didn’t that you don’t want to be in a hurry, let the roots fill the plug nicely, then transplant in to bigger pots etc.
Too much hurry equals broken roots and plant struggling to get going again with few leaves.
Interesting your note re sand. I have only used sieved bark fines, as a bit old school also.
Enjoy the journey and looks like you will have some nice JM’s to work with.
Charles
 
An update on these. Today i had some time to pull the seedlings from the plugs and plant in larger pots. most around 3" square. All have really started growing well in the past month. Even the first seedling that i pulled from the plug, in the spring when it had its first set of true leaves out, is now growing well (it sat with its first set of leaves for months without doing a thing). Though I have potted some others already, this is the largest batch yet this year. Overall seems like the ones started in the plugs with the bonsai soil on bottom and potting soil on top have done the best.

Some notes i have learned. The ones that have been planted out that have done best, done best being that they started growing almost immediately were the ones that filled the plug up completely and pulled out rather easily and compact. I did try and gently remove the potting soil / sand from the tops as there wasn't much roots in these anyways. Definitely no roots in that dam sand. Basically i just up-potted these, trying to minimize how much i disturbed the roots.

Here is a pic of the overall lot that were potted up. I remembered about half way through to plant them on an angle, so alot of them are sticking straight up. Plan to wire these in the coming spring 2019. Some have also been planted out in groups up to four.

IMG_3218.jpg

Here is the tallest of the seedlings planted out.
IMG_3222.jpg

This seems like it could be a nice tree.
IMG_3220.jpg

Another possible red seedling.
IMG_3221.jpg

Another red one I laid way over in this little plastic bonsai pot for fun.

IMG_3219.jpg
 
An update on these.


Robert, its very coincidental that you replied to this thread when you did. I was just looking up JM seedlings for sale, but not finding any. Would you be interested in selling a few of these?
 
Best time to prune j. Maples is late winter / early spring imho. When the buds start to enlarge but before they truly start to grow. At least that's what I've found from experience IMHO. Cheers.

Remember though that Pseudomonas syringae is transmitted at this time, paradoxically through cell crystallization so seal immediately.
 
An update on these. Today i had some time to pull the seedlings from the plugs and plant in larger pots. most around 3" square. All have really started growing well in the past month. Even the first seedling that i pulled from the plug, in the spring when it had its first set of true leaves out, is now growing well (it sat with its first set of leaves for months without doing a thing). Though I have potted some others already, this is the largest batch yet this year. Overall seems like the ones started in the plugs with the bonsai soil on bottom and potting soil on top have done the best.

Some notes i have learned. The ones that have been planted out that have done best, done best being that they started growing almost immediately were the ones that filled the plug up completely and pulled out rather easily and compact. I did try and gently remove the potting soil / sand from the tops as there wasn't much roots in these anyways. Definitely no roots in that dam sand. Basically i just up-potted these, trying to minimize how much i disturbed the roots.

Here is a pic of the overall lot that were potted up. I remembered about half way through to plant them on an angle, so alot of them are sticking straight up. Plan to wire these in the coming spring 2019. Some have also been planted out in groups up to four.

View attachment 199823

Here is the tallest of the seedlings planted out.
View attachment 199820

This seems like it could be a nice tree.
View attachment 199821

Another possible red seedling.
View attachment 199822

Another red one I laid way over in this little plastic bonsai pot for fun.

View attachment 199824
hello ! As you have many many trees, you could try to put 5 or 7 trees of the same specie in 5mm holes dug in a wood (or plastic) plate. The holes spaced out by 1 inch. Then you put the plate with the trees under the soil. This way the trunks will grow and be choked and then make new roots. And a few years later, you'll get a multitrunk tree fused at the nebari. you can even cut some trunks to keep 3, 2 or 1 trunk : With 1 trunk left, you'll have a single tree with a good large base :cool: I think it could be interesting to try.
 
hello ! As you have many many trees, you could try to put 5 or 7 trees of the same specie in 5mm holes dug in a wood (or plastic) plate. The holes spaced out by 1 inch. Then you put the plate with the trees under the soil. This way the trunks will grow and be choked and then make new roots. And a few years later, you'll get a multitrunk tree fused at the nebari. you can even cut some trunks to keep 3, 2 or 1 trunk : With 1 trunk left, you'll have a single tree with a good large base :cool: I think it could be interesting to try.

That is something definitely in the plan along with some other versions of that technique.
 
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