Question
How deep should I plant sunflower seeds in the ground directly in the ground ?

Answer
The general rule of thumb is to plant most seeds 2X their thickness. Sunflowers, depending on the species, are among the largest seeds.  I have always planted them 3/4" deep and have had good success with germination. Just be sure to cover them with a light layer of shredded leaves or grass clippings to preserve moisture.

Good luck, and please write again if you ever need assistance.

Regards,

Mike