Though most home gardeners opt to purchase established crowns to start their asparagus beds due to the time involved in growing from seed, asparagus can be grown from seed either indoors in starter trays or direct seeded into the garden.
How to Start Asparagus Seeds Indoors
Seeds should be started 10-12 weeks prior to the last frost of the season.
To start indoors, fill individual peat pots or a starter tray with individual cells with a fertile commercial soil starter and moisten. Plant seeds ½” deep, one per pot or tray. Place the starter tray on a screen so that the roots will be easier to lift from the container when you are ready to transplant. Place in a room with a constant temperature of 75-85°F. After seedlings emerge, they can be moved a room with a constant temperature of 70-75°F during the day and 60-65°F at night. Make sure the seedlings do not overheat. High temperatures will result in a weakened root system.
Transplants can be planted in the garden after the threat of frost has passed and the soil has reached at least 50°F.
How to Direct Seed Asparagus
Direct seeding can be done but does present a few issues. Seed beds must be prepared with precision to encourage optimal root growth and development. Because asparagus seeds are slow to develop, weeds are also an additional problem that are not present when started indoors.
Direct seeding can be done as soon as the threat of frost has passed and the soil has reached at least 50°F.
To direct seed, dig furrows 6” deep, spaced 18-36” apart. Build small mounds within the furrows so that the single seeds are spaced 3” apart. Plant 1” deep. The soil must be kept moist but not soaked during this germination process. As the seedlings begin to emerge and grow, the furrows can be slowly filled in until ultimately they are filled in to ground level.
“Vegetable Crops.” Asparagus Information Bulletin. N.p., n.d. Web. 26 Feb. 2014. <http://vegetablemdonline.ppath.cornell.edu/factsheets/AsparagusInfo.htm>.
“Vegetable Overview: Asparagus.” Sophisticated Gardening. N.p., n.d. Web. 26 Feb. 2014. <http://www.sophisticatedgardening.com/1175.html>.