How to Germinate Japanese Maple Seeds:
In order to get Japanese maples to germinate they like a period of cold called stratification. You can simulate stratification in a plastic bag filled with sand or peat in the refrigerator for a couple months after the seeds turn brown. The refrigerator simulates the cold temperatures of mother nature. This past winter was one of the coldest we have seen in a long time which is why I think so many little Japanese maples germinated. The seedlings were naturally stratified - at least the cold winter was good for something!
Today we spent some time transplanting some of the maples into pots. Each of the seedlings had grown two good leaves beyond the initial cotyledons before we transplanted them. In total we now have 60 Japanese maple seedlings comfortably resting underneath the shade. They will stay there until they are old enough to be planted in larger pots or in the landscape. This is just a fraction of the seedlings, we just ran out of soil to plant them! I can foresee another transplanting of 50-150 seedlings in our future. Now what are we going to do with 200+ Japanese maples?