Q.How Many Ounces Of Water Should I Put In A Container?
The container is 5 inches deep, 5 inches wide, and 15 inches long. I planted a row of nasturtium seeds and scattered lettuce seeds. I planted them in 4 1/2 inches of potting soil and covered them with 1/4 inch of soil. I will check for soil dampness with a dowel stick.

Certified GKH Gardening Expert
You can start out spray misting the seed bed to keep them moist. Once they sprout, increase the amount of water. When they begin filling out the container, water enough to run out through the drainage holes.