Asparagus Growing Guide

Asparagus is a perennial vegetable which can grow up to 5′ if let go. Asparagus is grown for its edible stems and can take 2–3 years to establish a new asparagus bed especially if growing from seed, but once you’ve done that, you can expect to harvest asparagus every spring for up to 20–30 years.

Asparagus; originally a native of Europe, Northern Africa, and Western Asia, is now grown worldwide. Asparagus 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 asparagus originated near the sea, it’s more tolerant of saline soils than most other vegetables.

• BOTANICAL NAME: Asparagus officinalis
• PLANT TYPE: Vegetable
• GROWTH CYCLE: Annual
• SEASON: Spring Summer Fall Winter
• USDA ZONE: 4a-9b
• LIGHT: Full Sun / Partial Shade
• SOIL TYPE: Loamy Sandy
• YIELD: 0.5-2 lbs. per plant
• SQUARE FOOT GARDEN: 1 plant per square foot
• Germination Soil Temperature: 50-70°F, optimal 65°F
• GERMINATION: 10-15 days
• MATURITY: 730 days from first planting
• HARVEST: 730 days
• SEED DEPTH: 1″
• PLANT SPACING: thin 12″
• ROW SPACING: 15-18″
• 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

NOTE: It is recommended that you start 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 seed. Asparagus can be grown from crowns with large (but not tightly packed) roots. Asparagus seeds remain viable for three years when stored properly.

CLIMATE 

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.

LIGHT

Full sun or partial shade

SOIL

Prefers sandy or loamy, well-drained soil. If soil does not drain well, consider planting in 12 deep gaerden beds over furrows in the ground. A pH of 6.0 to 6.5 will keep plants healthy and nourished. 

 CARE

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.

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.

PESTS

• Asparagus beetles
• Aphids
• Thrips
• Slugs
• Snails
• Cutworms

DISEASES

• Crown rot
• Rust
• Wilt

COMPANIONS

Grows well with dill, carrots, tomatoes, parsley, basil, and parsley. Avoid onions, garlic, chives, leeks, and potatoes.

HARVEST 

Do not harvest 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 thin stalks on the plant to grow into ferns in subsequent seasons. 

STORAGE

Will keep in the refrigerator for 1 to 2 weeks. 

PRESERVE

Can be pickled or 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.

NUTRITION

Contains significant amounts of fiber, antioxidants, and vitamins K and B. Is also a good source of most major minerals. Nutrition Facts  

MEDICINAL

Has historically been used for decreasing cholesterol and helping with digestion issues such as constipation and irritable bowel syndrome 

PLANT YOUR ZONE                         Cooperative Extension Service By State

 * Asparagus is a perennial and does not produce edible stems in its first year. Start seeds indoors 12-14 weeks before the average last frost date. Plant seedlings outside when soil can be worked in spring, usually 2-4 weeks before the average last frost date. Most people plant crowns or seedlings instead of growing from seed.