am looking to build up a nursery, and garden, of unhybridized
fruit trees. have some wonderful loquat trees in town, and
thought I would start by sprouting seeds from my favorite
trees.

any advice on how long to wait before planting them,
and other tips from the experienced fruit tree
experts here?

this week planted two mulberry trees, and two
fig trees. and have access to many fig trees I plan
to practice air-layering (propagation) on.

for all our sacred relations,

Millennium Twain

...

I would agree with the information in the link BigEasyJock provides -- plant your loquat seeds immediately. If the seeds dry out, the plant embryos within will probably die.

Most of my loquat grafting attempts have been made with bud-shield grafts -- but I've gotten very low success rates using this method. Some suggest that it is better to employ whole-scion grafts (cleft or whip), using material from twig terminals -- and I think that I may try using this method more in the future. The one time I used it in the past, I got fairly good results.

There's a wild loquat on a creek bed near my place - I picked the fruit and ate it (to the amazement of She Who Must Be Obeyed) and pushed one seed in the soil at the front of the house, one at the back fence and one on the side fence - I now have three seedlings coping quite well with the mess I have to call soil here.

enjoy