Asparagus is a perennial vegetable which can reach heights of 5′ and is grown for its edible stems. It can take 2–3 years to establish a new asparagus stand, but once you’ve done that, you can expect to harvest it each spring for up to 20–30 years. Originally native to Europe, northern Africa, and western Asia, it’s now grown around the world. It prefers climates with cool winters and will die back each year, sprouting new stems and feathery stalks of leaves in spring. There are usually male and female plants, with males producing yellow or white flowers and females producing smaller flowers followed by berries that will ripen to red. Because it originated near the sea, it’s more tolerant of saline soils than most other vegetables or weeds.
The Jersey Giant variety was developed as a hybrid at Rutgers University and is becoming increasingly popular due to being less susceptible to rust and crown rot than more traditional varieties. As an all-male variety, it doesn’t produce berries, allowing the plant to send more energy to its stalks and improve yields.
Seed Depth: 1″
Space Between Plants: 12″
Space Between Rows: 15–18″
Germination Soil Temperature: 50–70°F
Days for Germination: 10–15
Sow Indoors: Start your seeds indoors 3–4 months prior to the average last frost.
Sow Outdoors: Transplant seedlings outdoors as soon as the soil can be worked. If planting seeds directly outdoors, wait until all chance of frost has passed.
Vegetative: It is recommended that you start your asparagus plants from crowns since you’ll need to wait an extra growing season (3 years instead of 2) before you start harvesting if starting from seeds. Asparagus can be grown from crowns with large (but not tightly packed) roots.
Prefers somewhat cooler weather, so the best time to plant is in the early spring in most climate zones. Plants will not grow well once temperatures reach a consistent warmth of over 75°F.
Natural: Full sun to partial shade.
Soil: Prefers sandy or loamy, well-drained soil. If soil does not drain well, consider planting in beds or mounds. A pH of 6.0 to 6.5 will keep plants healthy and nourished.
Soilless: Grows well in soilless mixes that contain perlite or rock wool.
Hydroponics: Will thrive in a hydroponic system in media such as coco coir.
Water: Requires moderate levels of water. Although asparagus likes consistently moist soil, it does not like to be in standing water, so be sure to plant in well-draining soil. Water regularly within the first two years. Following this time period, plants will require less watering, but be sure to keep an eye out for limp spears as this can indicate dehydration.
Nutrients: Although not required, a balanced nitrogen, phosphorous, and potassium fertilizer can help plants grow, particularly in the earlier stages.
Foliar: Spray with a compost tea both in the fall and spring to help the plant grow.
Pruning: Beds can be cut back either in the fall, after all the foliage has died, or in the spring. There are two varying schools of thought on when to cut: advocates for fall pruning say it keeps pest populations down, while those who advocate for spring pruning say ferns keep the plants protected from frosty weather. Whichever season you choose, cut the plant’s ferns down to about 3″ above the soil and cut off the crowns of any remaining stalks to encourage new fern growth in the following season.
Mulching: Most mulch types can be used to keep soil moist.
Companions: Grows well with dill, carrots, tomatoes, parsley, basil, and parsley. Avoid onions, garlic, chives, leeks, and potatoes.
Harvest: Do not harvest your asparagus until it has become established (2 seasons). To harvest, wait until stalks reach 6 to 12″ and either cut or snap off near the bottom of the stalk. Leave the leaves to help the plant grow stalks the following year. Leave thin stalks on the plant to grow into ferns in subsequent seasons.
Storage: Will keep in the refrigerator for 1 to 2 weeks.
Fun Fact: Asparagus, when planted from seed, generally grows into 50% female plants and 50% male. As the female plants produce berries in addition to stalks, commercial operations generally grow male plants via cloning since the berries detract energy from stalk production.
Preserve: Can be frozen by trimming the base of stalks, blanching, and placing in freezer bags.
Prepare: To prepare stalks, trim the bases to take off the tough sections. Spears should then be rinsed and steamed, baked, or boiled.
Nutritional: Contains significant amounts of fiber, antioxidants, and vitamin(s) K and B. Is also a good source of most major minerals.
Medicinal: Has historically been used for decreasing cholesterol and digestion problems such as constipation and irritable bowel syndrome.
For a quick and healthy side dish, try this Roasted Asparagus recipe.