Sorry to hear about your medical problem, FHK. I can readily identify/sympathize with you---literally.
You need the fertilizer in the soil below your seed, optimally, to prevent burning of the sprouted seedlings. Apply your fertilizer to your tilled plot, till the fertilizer into the soil, broadcast your seed over the plot, and lightly cover/drag in the seed. Be very careful not to drag in (plant) small seed such as brassicas, clover, etc., too deeply.
When your plants are about 2 months old, you can lightly fertilize them again.
Best of luck on your deer plot.
