It's been a couple weeks now since the first Coffea seedlings emerged from the vermiculite, which may be a good time to report on what's happened since then.
The news I find most interesting is that, of the two groups of seedlings (those dried for eight weeks prior to sowing, and those dried for only four or five days prior to sowing), the eight-week group is clearly and obviously doing much better than the five-day group. By this point in the process, I've gotten 100% germination (18/18) from the eight-week group --
-- and only 11% (1/9) from the five-day group:
Obviously there's still time for the remaining eight seeds to sprout, but they only have a month left, and I'm not optimistic about them. So we've learned something. If you're going to sprout Coffea seeds from berries, here's a procedure that works:
1) Remove the seeds from ripe berries.
2) Soak the seeds in water for 24 hours.
3) Remove the seeds from water and let dry for eight weeks in a warm, dry spot with good air circulation and no sun.
4) At the end of the eight weeks, soak the seeds in water again for 24 hours.
5) Plant the seeds 1 1/2 inches (~4 cm) deep in damp but not sodden vermiculite, ideally in a pot that's taller than it is wide, and cover the pot to keep in moisture.1 Place under a light source, in a warm location,2 and wait; you should see the first sprouts in about a month.
But the specific occasion for the post is that there are now cotyledons3 visible:
Which is exciting.
Also noteworthy: a lot of the seeds had some gray fuzzy fungus on them once they emerged from the vermiculite. This doesn't appear to have affected the seedlings or their germination any, however worried I was to see it initially.
It's possible that the black stuff on the seed coat, two pictures up, is another fungus, or is related somehow to the first fungus. All I can tell you at this point is that it's surprisingly fine and sooty.
The next Coffea update will probably be when they all get transplanted to soil; I have no idea when that will be, though. I'm not sure how long they can (or should) continue to grow in the vermiculite, and I don't want to try to transplant until I'm fairly sure they have root systems that can handle the shock. So we'll have to see how it goes, I guess.
2 The basement's not really all that warm. Maybe 72-76F / 22-24C.
3 ("Seed leaves")