Asparagus is a perennial. Once established it will faithfully produce year after year for 20 years or more with only minimal maintenance.
Location: Plant it on the North side of your main garden in full sun. It gets tall and can shade your other plants. It will be a permanent feature of your garden so plan carefully.
Soil: Asparagus likes a pH around 7; high N; moderate p and k. Take soil samples in the fall before planting the following spring and make appropriate amendments. Cultivate the soil deep, 16 inches or so and work in generous amounts of compost—composted manure is ideal.
Planting: In spring about the time daffodils bloom is good for most regions of the U.S. Fall and winter is best for the very warm regions—south and southwest.
Crowns—preferred: For Jersey Hybrid; dig a hole or trench about 6 inches deep, add an inch or two of compost and place the crowns 18 inches apart spreading the roots out evenly and cover with 2 inches of soil. As the ferns grow during the summer, add a couple of inches of soil. As the plants grow add a couple more inches of soil at a time until you have a raised berm. Do the same for open pollinated varieties such as Martha Washington except dig the holes or trenches 12 inches deep instead of 6.
Seeds: Same as crowns except plant the seeds ¼ to ½ inch deep and very slowly, as the plants grow, add soil until you have a bermed (raised) bed.
Good companions: Basil, parsley, tomato.
Bad companions: Onion, chive, garlic, leek.
Harvesting: Harvest crown plantings after 2 years—not before or you will kill or damage the establishment of your asparagus beds. For beds started from seed, wait at least 3 years before harvesting. First harvests should be light. Don’t over tax your plants just yet.
Care and Maintenance: Keep your beds free of grass and weeds. Generous mulching will help with weed and moisture management.
Mulch makes weeds and grasses easier to hand pull while holding moisture in the bed. Be careful of weeding with a hoe as going too deep will injure or destroy the underground stems.
Asparagus likes lots of water but don’t drown it. That’s where the raised berms come in.
Every fall after frost or when the ferns have turned brown or yellow, cut the ferns to about 2 inches above ground. Top dress the beds with a light application of fertilizer and 2 or more inches of compost or rotted manure; add fresh mulch and your beds are “bedded” for the winter.
In the spring, add another light application of fertilizer along with 2 or more inches of good compost and/or rotted manure and a light topping of mulch. You will add more mulch after harvesting has ceased. Stop harvesting when you notice the spear stems getting thinner. They should not be allowed to get thinner than a pencil. I don’t let mine even get that thin.
Diseases: Rust is the most common in older varieties and can be prevented by choosing rust-resistant varieties. Treat affected plants with mancozeb.
Pests: Asparagus Beetles are the most common pest and can be controlled with carbaryl, malathion, or rotenone while keeping the beds free of weeds and grass.
