Grow like weeds. Plant out now in pot of rich compost or potting mix, they will sprout in late march or april. They need the winter cold to germinate.

You can generally find hundreds of seedlings around mature trees in spring, and the transplant nearly 100% in the 4-6 real leaf stage.

George

Exactly as George said - they fall from the trees, lay dormant until March/April, then sprout and grow. I pot up a lot of them every spring. Some I leave in the ground until the next spring, when they will be from 6-12" tall. 99% success rate for me.

I wish this was true for me.I have a beautiful red and a green tree that was here when I moved in.I have been here 3 yrs. and have not had one single seedling.I had seeds last fall.I put some in moist potting soil in the fridge,I now have sprouts after 4 mos.I was told on ws forum to pot them up and one said under lights,another said in carport til spring.I am opting for carport since I do not have a light set up.That is really all the info I know.Good luck..
moonphase

So, can I sow dried seeds with success then? I traded for some seeds and wgen they arrived, appeared to have been dried out for quite some time.

No, I don't think dried seed will germinate quite that easily for you - Fall sowing fresh seed may have resulted in easy seedlings this Spring. Clothiers: Acer palmatum , Japanese maple, seed should be collected from the tree before it dries, then sown directly outdoors for germ. the following spring.

To try to mimic what mother nature would have done with these in Fall, try pouring hot water over the seeds, let stand in the water for 24-48 hours. Drain water from seed, put them in a zip lock with a little moist sterile sand or vermiculite at room temperature for 60 days, then cold stratify for not less than 60 days and up to 120 days before bringing them back to warm.

I usually dig up seedlings but tried sowing dried Red & Laceleaf maple seeds for the first time this year and have had pretty good success. I used a period of cold, moist stratification then planted them and am using bottom heat. It took about 2 weeks for the seeds to start germinating and I still have some coming up 4 weeks later. The Laceleaf maples took much longer than the Red maples to germinate. I don't remember how long I had them in moist sphagnum moss in the fridge, maybe 2 months? I'm also trying to winter sow some of them. I'll find out if that worked in the spring.
Karyn

I noticed that my mature japanese red maple must have dropped seedlings that have spouted on their own. They look like tiny leaves springing up from the ground. I want to preserve them, but they are in a crowded area with hastas and other foliage. Can I dig them up and transplant them? Any ideas??? Thank you.

I have potted these up before, but with no success - any tips?

Last November (2010) I bought 500 Japanese red maple seeds
I followed the instructions: I kept in the warm water for 48 hours and set up in a plastic bag with mixed pit moss + sand + perlite for 65 days.
I sowed the seeds outside on a semi-shade in the mixture of pit moss, sand and perlite on February, 28 2011.
I am in May 14, 2011 and I did not get any sprouts.
What did I do wrong?