How to Grow Jersey Knight Asparagus

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Jersey Knight Asparagus

Asparagus officinalis 'Jersey Knight'

vegetable

Jersey Knight is an all-male asparagus cultivar bred at Rutgers University, known for vigor, disease resistance, and high yields of thick, tender spears. All-male plants produce no seeds, directing energy entirely into spear production rather than berry formation. This variety is among the most popular commercial and home garden asparagus varieties.

Looking for a specific variety?

Jersey Prince Jersey Giant UC 157 Millennium Mary Washington

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Example Jersey Knight Asparagus timeline · Pittsburgh, PA (Zone 6b)

Plant Jersey Knight Asparagus
Around Apr 17

Near Pittsburgh's average last spring frost.
Tend & protect
Late spring–summer

Watering, feeding, and pest-watch reminders.
Harvest Jersey Knight Asparagus
Late summer into fall

Before the first fall frost (≈ Nov 8)

Sample dates for Pittsburgh, PA. Sign up to get exact Jersey Knight Asparagus dates for your own zip code.

Growing Conditions

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Sun: Full sun, minimum 8 hours daily; more sun increases yield and spear quality

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Water: Moderate watering, 1-1.5 inches per week during growing season; keep soil consistently moist but not waterlogged; reduce watering in fall to harden crowns for winter

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Spacing: 18 inches

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Days to maturity: 2-3 years from planting to full production (asparagus is a perennial, not typically harvested first year)

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Planting depth: 8-10 inches for crowns; plant dormant crowns in early spring 8-10 inches deep with soil mounded over them

Soil

Type: Well-draining sandy loam or loamy soil with high organic matter

pH: 6.5-7.5

Amendments:

Compost or aged manure (2-3 inches worked into top 12 inches) Perlite or coarse sand if drainage is poor Kelp meal for trace minerals Bone meal for phosphorus

Growing Zones

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Zones 3-8; performs best in cooler climates with adequate winter chilling

3a 3b 4a 4b 5a 5b 6a 6b 7a 7b 8a

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Growth Stages

Crown Establishment (Year 1)

Full growing season (spring through fall frost)

Asparagus crowns develop fine root systems; weak shoots emerge and grow into fern-like foliage to build crown reserves

Do NOT harvest spears in first year; allow all shoots to grow to full height (3-5 feet); keep weeds minimal; water consistently; mulch to conserve moisture and regulate soil temperature

Root & Crown Development (Year 2)

Full second growing season

Underground crown expands with more buds; above-ground growth becomes bushier with denser fern foliage; light harvesting may begin late in season

Harvest lightly for 2-3 weeks only in late spring of second year; allow remaining spears to mature into fern for photosynthesis; fertilize with balanced fertilizer after harvest period ends; maintain consistent moisture

Productive Phase (Year 3+)

Ongoing; 15-20+ years of production from well-maintained bed

Crowns mature and produce abundant thick spears; plant reaches full vigor with dense fern canopy; harvest period extends 8-10 weeks annually

Harvest spears 6-8 inches tall by snapping or cutting below soil surface; harvest daily or every 2-3 days during peak season; stop harvesting when spear diameter noticeably decreases (usually late June/early July); allow remaining spears to mature into fern; apply 2-3 inches compost/mulch annually in early spring

Senescence & Dormancy (Fall/Winter)

Late September through March/April (varies by zone)

Fern foliage yellows and browns; plants die back to ground; crowns enter cold dormancy period

Cut back dead foliage to 1-2 inches above soil line in late fall after frost (late October/November in most zones); do not remove foliage too early as it continues to build crown reserves; add 1-2 inches compost mulch over crowns for winter protection in zones 3-5; in zone 8, light mulching helps with consistent soil temperature

Companion Planting

Plan your garden →

Plant with:

Basil Parsley Tomato Lettuce Spinach Thyme Dill Marigold Nasturtium

Avoid planting near:

Onion Garlic Allium species Fennel Potato

Common Pests

Hand-pick beetles and egg-laden stems; encourage beneficial insects; use neem oil or spinosad in early season if infestation is heavy; maintain clean beds by removing dead foliage
Similar to asparagus beetle; hand-pick; remove infested spears; use reflective mulches; encourage predatory wasps and beetles
Choose rust-resistant varieties like Jersey Knight; ensure good air circulation; remove and destroy infected foliage in fall; apply sulfur fungicide if infection is severe; avoid overhead watering
Plant in well-draining soil; rotate planting location; remove and destroy infected plants; plant disease-free crowns; improve soil health with compost
and
Handpick; use beer traps; copper tape barriers; encourage ground beetles; avoid excess mulch against emerging spears

Uses

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Fresh Vegetable & Cooking

Culinary

Jersey Knight spears are prized for their tender texture and sweet, subtle flavor when harvested young. Excellent for grilling, roasting, steaming, sautéing, or blanching and freezing for winter use. [source]

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Nutritional & Health Properties

Medicinal

Asparagus is rich in folate, glutathione, and asparagine; traditionally used to support urinary and kidney health. Contains bioactive compounds with potential anti-inflammatory and antioxidant properties. [source]

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Preservation & Storage

Household

Fresh spears store 3-5 days in refrigerator; excellent candidate for freezing, canning, or pickling to preserve abundant spring harvests. [source]

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Pollinator & Beneficial Insect Support

Wildlife

Mature fern foliage and flowering (in unharvested spears) provides habitat and food sources for beneficial insects, native bees, and predatory insects that control garden pests. [source]

This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.

Harvest Tips

Begin light harvesting in year 2 for 2-3 weeks; in year 3 and beyond, harvest for 8-10 weeks from spring emergence until spear diameter drops significantly (usually late June/July). Snap or cut spears 6-8 inches tall just below soil surface; harvest daily or every 2-3 days during peak season for maximum tenderness. Jersey Knight produces uniformly thick spears ideal for fresh eating, grilling, or freezing. Stop harvesting when spear thickness noticeably decreases to allow crown recovery and fern growth for next season.

Fun Facts

🌱 Jersey Knight is an all-male variety—a significant advantage because female plants waste energy producing seeds in red berries, while males direct all resources to spear production. This can increase yields by 25-30% compared to mixed-sex varieties.
🌱 Asparagus is one of the longest-living perennial vegetables; a well-maintained Jersey Knight bed can produce excellent harvests for 15-20+ years, with some established beds exceeding 30 years of productivity.
🌱 The name 'Jersey Knight' honors both its New Jersey breeding origin at Rutgers University and its vigor; the variety was released in the 1970s and remains the standard for home and commercial growers seeking disease resistance and consistent thick spear production.

Gardening Terms

New to gardening? Learn about terms used in this guide:

Annual Compost Crown Cultivar Full Sun Mulch pH

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