Having sown hundreds of maple seeds over the years, this year I thought I'd put together a pictorial of my method - which I have found the most reliable. While it involves stratification (which some may dismiss as unnecessary), it allows the eradication of any unviable seed to give a result of 100% germination rate. I sow trident maple seeds every year for both bed-growing and root-grafting stock, and this method assures me 100% strike rate (assuming the seed is fresh). The method also works for Japanese maple:
1. Obtain your seed from a reliable source - the most awesome seed I have ever used can be sourced here on Ausbonsai
. Maple seeds are ripe for harvest around mid-May.
2. At around 8-12 weeks from the beginning of September (Spring), start the stratification process. First, soak in water for 36-48 hrs.
3. After the soaking period, eliminate and discard any seeds that are still floating on the surface of the water - these are usually unviable seed.
4. Then, take a handful of sphagnum moss, drench with water and squeeze in your hand to ring-out any excess water. The sphagnum should be damp, but not soaked.
5. Add the viable seeds, and mix in by hand.
6. Place the sphagnum/seed mixture in a snap-seal plastic bag, and place in the fridge.
7. After about 8 weeks, check the seed each week until you notice they are starting to germinate. This year it took mine 10 weeks.
8. Take the seeds out, and carefully sow the sprouting seeds into a good seed raising mixture. Use a chopstick to create the hole for the seed to ensure the delicate root is not damaged. Water in the seeds.
9. After a couple of weeks, your seedlings should look like this:
10. This time next year, your seedlings will look like this:
Cheers.
