Every year I plant morning glories from fresh seeds, in containers (the long, rectangular kind). They always take a bit of time (1-2 weeks) to sprout, and after that, really take off (I hang some twine on the walls of my terrace and they climb up like crazy).
This year, I planted more seeds than I ever have - different varieties of morning glories, as well as some moon flowers. I soaked the seeds overnight as I always do (for about 24 hours, and I'd say the seeds double, if not triple in size). Planted them as I always do (about a 1/4" deep as per the directions), in a "zigzag" pattern in the planters, about 4" or so apart. Probably about 40 seeds in total.
3 weeks later, only 2 have broken through the soil, and even those are not looking so good (very "wrinkly" and weak-looking). No sign of the others. I've been watering regularly, and the weather seems about the same as it always (maybe a few nights that have been colder than average).
Basically I've done exactly the same thing that I've done for years, and it's not working for some reason this year. Any ideas what could be wrong, or what I could to improve the process? I just planted a whole new batch of seeds (in the same planters) a few days ago.
EDIT: I should add - I'm in New York City, and the plants get tons of sun.