Add an airy potting mix to a planter with drainage holes. Buy or make your own growing medium by uniformly blending 1 part sand, 2 parts peat moss and 2 parts loam. Fill the pot to within 1/4 inch of the rim.
Dig a hole in the potting mix with your finger. Make it in the center of the planter and twice as deep as the seed's diameter. Place the asparagus fern seed in the hole and fill it with soil.
Water the seed until the excess flows out of the pot's drainage holes. Keep the seed hydrated by moistening the potting mix whenever the surface begins to dry.
Move the container to an area where the temperature stays between 60 and 70 degrees Fahrenheit to promote seed germination. Place the pot on an electric seed-propagation mat to maintain the soil at the right temperature, if necessary. Germination takes three weeks to a month.