My experiment of growing cranberries from seed was very successful--all of my seeds germinated. This was back at the end of April. Once I saw those tiny leaves poking out of the soil, I took off the plastic bag and made sure to keep the pot well watered. In May, I transplanted them to a larger bed.
The larger bed was about 5 feet by 5 feet. I lined the bottom with contractor-grade plastic, poked some holes in it for drainage, then filled it with two bales of peat moss. It took a long time to get all that peat moss wet--for some reason, dry peat moss actually repels water. I had to get in there and knead the water in with my hands, and keep watering.
I transplanted all the seedlings into that bed. Here's a closeup of what a couple of them look like now:
Commercial cranberry growers propagate their cranberries from cuttings, so in any commercial planting of cranberries, they are probably all genetically identical. When you grow from seeds, each seed has different genetic material, just like all children, even those from the same parents, are different from each other. I am very curious about how these differences will show up in my plants once they start making berries. Different berry size? Different color? Different taste? Every year I will save a few more seeds from our holiday cranberry bag and add to my this project--eventually I'll have a really diverse bed of cranberries, and that should be interesting!