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How to Grow Alfalfa 'Vernal WL 320'

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Alfalfa 'Vernal WL 320'

Medicago sativa L.

herb

Vernal WL 320 is a cold-hardy, leafy alfalfa cultivar bred for superior forage quality and winter hardiness. This perennial legume is widely used as a high-protein livestock feed and cover crop, with excellent regrowth after cutting. It features reduced stem-to-leaf ratio and improved digestibility compared to standard alfalfa varieties.

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Example Alfalfa 'Vernal WL 320' timeline · Pittsburgh, PA (Zone 6b)

  1. Plant Alfalfa 'Vernal WL 320'

    Around Apr 17

    Near Pittsburgh's average last spring frost.

  2. Tend & protect

    Late spring–summer

    Watering, feeding, and pest-watch reminders.

  3. Harvest Alfalfa 'Vernal WL 320'

    Late summer into fall

    Before the first fall frost (≈ Nov 8)

Sample dates for Pittsburgh, PA. Sign up to get exact Alfalfa 'Vernal WL 320' dates for your own zip code.

Growing Conditions

☀️
Sun: Full sun, 6+ hours daily (8+ hours ideal)
💧
Water: Moderate to deep watering; once established, drought-tolerant due to deep taproot. Needs 15-20 inches annual precipitation or supplemental irrigation. Avoid waterlogging.
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Spacing: 6-12 inches between plants in rows; rows 24-36 inches apart for mechanized farming inches
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Days to maturity: 50-60 days to first cutting; full productivity in year 2
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Planting depth: 0.25-0.5 inches (shallow planting critical for germination)

Soil

Type: Well-draining loamy to clay loam soil with good calcium content
pH: 6.5-7.5
Amendments:
Lime to raise pH if below 6.5 Phosphorus and potassium fertilizers Compost or well-rotted manure for organic matter

Growing Zones

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Zones 3-7, with exceptional cold hardiness to zone 2

2a 2b 3a 3b 4a 4b 5a 5b 6a 6b 7a 7b 8a

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Growth Stages

1

Germination & Seedling

2-3 weeks

Small cotyledons emerge, developing true leaves. Plant is delicate and vulnerable to competition.

Keep soil consistently moist but not waterlogged. Control weeds aggressively. Avoid grazing or cutting during first 6-8 weeks. Ensure good soil contact.

2

Vegetative Establishment

4-6 weeks

Plant develops compound leaves and strong taproot system. Multiple stems emerge from crown.

Continue weed control. Light rolling may improve soil contact. Monitor for seedling diseases. No cutting recommended until plant has 6-8 leaves.

3

Bud Formation

1-2 weeks

Flower buds form at stem terminals. Plant reaches optimal forage stage (boot to early bloom).

This is the ideal harvest window. Monitor closely for development. High digestibility and protein content at this stage.

4

Flowering & Seed Production

2-3 weeks

Purple flowers bloom along stems. If left unharvested, develops seed pods.

Cut before full bloom for maximum forage quality. Overblown alfalfa has reduced nutritive value. Allow regrowth to 6+ inches before next cut.

5

Dormancy & Winter Hardiness

4-6 months

Plant enters dormancy in fall; Vernal WL 320 develops hardened crown for winter survival.

Cease cutting 6 weeks before first hard frost to allow winter preparation. Protect from winter grazing. Deep snow cover beneficial in colder zones.

Companion Planting

Plan your garden →

Plant with:

Orchardgrass Timothy grass Bromegrass Birdsfoot trefoil Sainfoin

Avoid planting near:

Black walnut (allelopathic effects) Sunflower Fennel Plants requiring acidic soil

Common Pests

  • Early cutting at optimal growth stage; insecticidal spray if larval populations exceed threshold; parasitic wasps provide biological control

  • Select resistant varieties like Vernal WL 320; spray with insecticidal soap or neem oil; encourage natural predators (ladybugs, lacewings)

  • Usually controlled by cutting; use Bacillus thuringiensis (Bt) if populations become excessive

  • and (Fusarium, Phytophthora spp.)

    Plant in well-draining soil; avoid waterlogging; use certified disease-free seed; crop rotation

  • Improve air circulation; cut infected foliage; resistant varieties; avoid overhead irrigation

Uses

🍳

Livestock Forage

Culinary

Superior-quality hay for cattle, horses, sheep, and other livestock. High protein content (15-22%) and excellent digestibility support animal growth and milk production. [source]

💊

Human Health & Supplements

Medicinal

Alfalfa sprouts and leaf meal contain vitamins K, A, C, and minerals; traditionally used to support bone health and blood clotting. Often consumed as sprouts or supplements. [source]

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Nitrogen Fixation & Soil Improvement

Household

Nodulated roots fix atmospheric nitrogen through symbiosis with Rhizobium bacteria, enriching soil naturally. Excellent as cover crop or green manure. [source]

🦋

Pollinator & Wildlife Support

Wildlife

Purple flowers attract bees, butterflies, and other pollinators. Provides forage for wild herbivores and habitat value in agricultural landscapes. [source]

🎨

Hydroponics & Sprouting

Craft

Alfalfa seeds are popular for home sprouting, producing nutritious microgreens in 5-7 days. Sprouts widely used in salads and health-conscious cooking. [source]

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

Harvest Tips

Cut at boot to early bloom stage (highest protein and digestibility). First cutting typically 50-60 days after spring emergence. Allow 30-35 days between cuts for regrowth. Typical harvest schedule: 3-4 cuttings per season in northern climates, 4-6 in southern zones. Cut to 2-3 inches stubble height. Cease cutting 6 weeks before first frost.

Fun Facts

  • 🌱 Alfalfa's deep taproot can reach 20+ feet into the soil, accessing water and nutrients inaccessible to shallow-rooted crops, making it remarkably drought-resistant once established.
  • 🌱 Vernal WL 320 was specifically bred by USDA researchers for extreme cold hardiness; 'WL' stands for 'Winter Legume' and can survive temperatures below -40°F with proper management.
  • 🌱 Alfalfa is one of the oldest cultivated crops, with records of its use dating back to ancient Persia (around 500 BCE) and valued by the Romans for cavalry horses.

Gardening Terms

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

Annual Cover Crop Crown Cultivar Full Sun Perennial True Leaves
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