When you are about to sow your vegetable or flower seeds, you will find that the colour of the very small seeds, blends in with the colour of the earth. My tip is to mix the seeds with a little baking flour. You will then sow the seeds evenly in the dark soil. The result being even rows, and not over seeded.
Rather than bending over to plant seeds in a long garden row, consider a pipe planter. Two versions are offered on this page with the new and improved one using a length of PVC pipe and a funnel.