Dig a trench approximately 1.5 inches deep soil with a gardening trowel. If the soil is extremely dry or sandy, dig 2 inches deep.
Drop seeds into the trench approximately 1 inch apart. Most soybean seeds will germinate, so it's unnecessary to overfill your trench with seeds, according to "The Old Farmer's Almanac."
Replace soil removed during digging. Ensure that seeds are loosely covered, and avoid pressing soil into the trench.
Sprinkle a mixture of phosphorus- and potassium-based fertilizer on the covered trench. Although fertilizer is not necessary, it may help your soybeans grow.
Water your trench within one hour of applying fertilizer. Apply a small amount of water and wait five minutes. Check the soil's moisture by pressing a bare fingertip into the surface. If particles of soil stick to your fingertip, you have provided enough water. If the soil feels mostly dry, provide more water and test again in five minutes.