Question
I have gone on several sites,nothing is really telling me what I want to know, I have a Japanese maple and have noticed for the first time, that it is making seeds, my question is this, and its simple when is the right time to take the seed and even attempt to germinate them, all i need to know is basically when should the seed be taken off the tree, instead of people trying to sell me seeds, that i hear are mostly dead.

Answer
Most Japanese Maple seeds ripen in the fall. Watch the tree and wait for the seeds to turn brown. The seeds are ready to be harvested when they are brown and can be easily removed from the tree. The seeds are attached to a wing, it's best to break the wing off before storing or planting the seeds. Once you have picked the seeds and removed the wing just place them in a paper bag and store them in a cool dry place until you are ready for them.

On or about the 100th day prior to your target planting date, take the seeds and place them in a Styrofoam cup or other container that will withstand some hot water. Draw warm to hot water from your kitchen faucet and pour it over the seeds. Most of the seeds will float, just leave them in the water overnight as the water cools down. 24 hours later most of the seeds will have settled to the bottom of the cup, drain off the water. Place the seeds in a plastic bag with a mixture of sand and peat or other suitable mix. Even light potting soil will work. The peat or soil should be moist, but not soaking wet. Poke some holes in the bag so there is some air circulation, and place the bag in your refrigerator for a period of 100 days.
 
After 100 days you can plant the seeds outside. If you have timed it correctly, you should be at or close to your target planting date. To plant the seeds just sow them on top of a bed of well drained topsoil or sterilized potting soil, and cover with approximately 3/8" of soil. Water them thoroughly, but allow the soil to dry out completely before watering thoroughly again.