Did you sow these outside? I'm trying to remember about coleus seeds; some flower/foliage seeds need light to germinate, some need dark. I plant my zinnias outside and cover the seeds with about a half inch of soil. I'm thinking the time I planted coleus seeds I just pressed them into the surface of the soil. Give it a little more time for germination. When the seedlings emerge, they will need a lot of light to grow straight and not become spindly. Some coleus are mostly shade plants; it depends on the particular variety, so filtered light is best. Zinnias outside need full sun .