I’ve never before tried starting either beets or spinach indoors, but I figured only two things could happen: failure, from which I could learn, or success, from which I could eat. Or something in-between. Transplanting beets would seem difficult, but a few years ago I watched a good friend do so with almost 100% success. Her "secret" was making a planting hole the same depth and diameter as the root ball, then carefully holding the root ball together and sliding it down into the hole, and then watering immediately.
So this morning, I started Red Ace F1 and Detroit Dark Red beets, and some Red Kitten F1 early flat-leaf spinach. Instead of my usual milled sphagnum, I covered these with moist coir. Like the sphagnum, coir is said to have antifungal properties, minimizing the chance of damping-off problems.
The Brassicas I planted 10 days ago are doing fine. They’re getting only bottom watering now, and I’ve begun thinning. Germination was above 90%, and there’s at least one healthy (so far!) plant in each cell.