I'm in zone 7b:

full sun location
deep soil mixed with compost, well-draining, but close to my water supply for times of drought

i direct sow my seeds after frost (April 15 here).

Keep soil moist, not soaked, and they germinate in just a few days

Once they are growing, I do not water unless the leaves are drooping in the morning. Then, I carefully water THE SOIL without getting it up on the plant.

Hope this helps. There are zinnia experts here. I'm not one, but I find these so easy to grow.

Cameron

Thanks Cameron.

I think I'm going to go ahead an have soil test. They are very easy to grow, yet, I received low germination this summer.