Did you germinate the seeds first? I find it's much harder to just plant the seed in soil, add some water and light and hope it flowers.

Take 6 sheets of kitchen paper towels, place the seeds in the middle. Pour some water over the seeds, enough to keep the area that the seeds are sitting in very moist. Fold the paper over itself so the seeds are sitting in the middle, and pour some more water overtop. Throw that in your drawer, stash box, etc... w/e. Presto, 3-5 days later you'll see some seeds have opened and others even have small roots comming out of the opening. Plant those in the soil, with the root facing the bottom of the planter.

Cheers.