Clovers & Legumes ·Growing Guide
Alfalfa
Medicago sativa
AlfalfaClovers & LegumesModerate (requires precise cutting management for longevity) Maintenance
The queen of forage crops. Alfalfa fixes more nitrogen (150-300 lbs per acre annually), produces more protein per acre, and persists longer (5-10+ years) than any other forage legume. Its taproot—reaching 6-15 feet and sometimes exceeding 25 feet—accesses deep moisture and minerals unavailable to any other crop. Alfalfa demands specifi...
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About Alfalfa
Alfalfa (Medicago sativa) produces the highest protein forage of any common crop (18-22% crude protein), the highest nitrogen fixation (150-300 lbs N/acre/year), and the longest productive stand life (5-10 years). It's the most widely grown forage crop in North America and the foundation of dairy nutrition across the continent.
Alfalfa's deep taproot is legendary—documented roots have exceeded 25 feet in ideal soils. This root depth provides drought tolerance that no other forage matches, accesses calcium and other deep minerals, and creates channels that improve soil structure for decades after the stand is terminated.
The management requirements are exacting. Alfalfa demands: pH 6.5+ (lime application is usually required in New England), excellent drainage (will not survive waterlogged conditions), precise cutting at 10% bloom (too early reduces root reserves, too late reduces quality), and never cutting below 2 inches (crown damage shortens stand life). It does not tolerate grass competition well and performs best in pure stands or carefully managed grass mixtures.
Dormancy rating matters for variety selection: Fall Dormancy 1-2 for zones 3-4 (fully dormant, maximum winter hardiness), FD 3-4 for zones 5-6, FD 5-7 for zones 7-8. Planting the wrong dormancy rating in your zone results in either winter-kill or reduced yield.
Alfalfa's deep taproot is legendary—documented roots have exceeded 25 feet in ideal soils. This root depth provides drought tolerance that no other forage matches, accesses calcium and other deep minerals, and creates channels that improve soil structure for decades after the stand is terminated.
The management requirements are exacting. Alfalfa demands: pH 6.5+ (lime application is usually required in New England), excellent drainage (will not survive waterlogged conditions), precise cutting at 10% bloom (too early reduces root reserves, too late reduces quality), and never cutting below 2 inches (crown damage shortens stand life). It does not tolerate grass competition well and performs best in pure stands or carefully managed grass mixtures.
Dormancy rating matters for variety selection: Fall Dormancy 1-2 for zones 3-4 (fully dormant, maximum winter hardiness), FD 3-4 for zones 5-6, FD 5-7 for zones 7-8. Planting the wrong dormancy rating in your zone results in either winter-kill or reduced yield.
Fit
Where It Shines
Best for
- Premium dairy hay production
- High-protein livestock feed
- Long-term stand (5-10+ years) on well-drained soil
- Nitrogen fixation for subsequent crops in rotation
- Deep soil improvement via taproot channels
- Drought-prone areas with deep, well-drained soil
- Mixed stands with orchardgrass or bromegrass
- Rotational value—corn yields increase 10-20% following alfalfa
Not ideal for
- Wet, poorly drained soils (root rot is fatal)
- Acidic soils below pH 6.5 (will not persist)
- Shaded conditions
- Short-term cover cropping (expensive seed; use clovers instead)
- Small garden scale
- Lawn or turf applications
- Casual management (alfalfa rewards precision and punishes neglect)
From Seed to Stand
Establishment & Growth
Germination
Days 5-7: First seedlings emerge. Days 7-10: Trifoliate leaves appear. Relatively fast germination for a perennial legume. Seedlings are upright with oval leaflets—distinctly different from clover's round leaflets.
Growth Habit
Perennial. Upright multi-stemmed growth from a crown. Deep taproot. 24-36 inches tall at harvest. Long-lived (5-10+ years with proper management).
Establishment Timeline
First emergence: 5-7 days. First harvest: 60-90 days. Full production: year two. Stand life: 5-10+ years with proper management.
Rates & Care
Seeding & Maintenance
| Seeding rate (new) | 15-20 lbs per acre (pure stand); 8-12 lbs per acre (mixed with grass) |
|---|---|
| Overseeding rate | 10-15 lbs per acre |
| Soil temp to germinate | 50-55°F |
| Mowing height | Cut at 10% bloom (when 10% of plants have open flowers); leave 2-3 inch stubble |
| Minimum mow height | 2 inches (cutting lower damages crown and shortens stand life) |
| First mow | At 10% bloom or 28-32 inches tall |
| Soil pH | 6.5-7.5 (requires near-neutral to slightly alkaline—the most pH-sensitive common legume) |
| Soil preference | Well-drained, deep loam to sandy loam. Absolutely requires good drainage—alfalfa roots rot in waterlogged conditions. Deep soil is essential for taproot development. |
| Nitrogen needs | None required—fixes 150-300 lbs N per acre annually (the highest N fixation of any common forage legume) |
Conditions
Tolerances
SunFull sun (6-8+ hours required)
ShadePoor (does not tolerate shade)
DroughtExcellent (one of the most drought-tolerant forage legumes due to deep taproot)
TrafficLow
ColdGood to Excellent (variety dependent; dormancy rating 1-5 scale)
HeatGood to Excellent
Hardiness Zones3-9 (dormancy rating selection critical for zone matching)
Step by Step
How to Sow
1
Step 1: Prep
Soil test/lime to pH 6.5-7.5; ensure drainage
2
Step 2: Fertilize
Inoculate seed; apply P and K (no N)
3
Step 3: Sow
Drill or broadcast at 15-20 lbs per acre
4
Step 4: Contact
Plant 1/4 to 1/2" deep; use cultipacker (Critical)
5
Step 5: Water
Keep moist during germination
6
Step 6: Mow/Establish
Harvest at 10% bloom; do not cut below 2"
Feeding & Timing
Fertilizing & Season
Fertilizer Recommendation
No nitrogen needed—alfalfa fixes its own. Phosphorus and potassium are critical (alfalfa is a heavy K consumer). Soil test annually and maintain adequate P, K, and pH. Boron and sulfur deficiencies are common in New England alfalfa—apply based on soil and tissue testing. Recommended: Wicked Growth P-K formula, annual soil testing program.
Find the right Wicked fertilizer →Seasonal Planting
Spring planting (April-May) most common in northern zones. Late summer planting (August) effective—allows fall establishment before winter dormancy. Spring-planted alfalfa should not be harvested more than once in the establishment year. Select dormancy rating appropriate for your zone: FD 2-3 for most of New England.
In Context
How It Compares
Alfalfa vs. Red Clover: Alfalfa produces more per acre, persists longer (5-10 years vs. 2-3), and fixes more nitrogen; Red Clover tolerates wetter, more acidic soils and establishes cheaper. Alfalfa vs. Ladino Clover: Alfalfa is higher yielding and deeper rooted; Ladino is lower-growing and spreads via stolons. Alfalfa vs. Birdsfoot Trefoil: Alfalfa yields more on good soils; Trefoil persists on poorer, wetter, more acidic soils and doesn't cause bloat. Alfalfa is the production champion—but only on suitable soils with precise management.
Answers
Frequently Asked Questions
What is alfalfa and why is it called the queen of forages?
Alfalfa (Medicago sativa), also known as lucerne, is a deep-rooted perennial legume considered the highest-quality forage crop in North America. It earns the title 'queen of forages' for its unmatched combination of high protein (16-22% crude protein), high yield (4-8 tons per acre annually), nitrogen fixation (150-300 lbs N per acre), and persistence (5-10+ year stands). Alfalfa's taproot penetrates 10-20+ feet, making it exceptionally drought-tolerant once established.
What soil conditions does alfalfa require?
Alfalfa demands well-drained soil with pH 6.5-7.5—it will not tolerate acidic conditions below pH 6.0 or waterlogged soils. Lime applications are often necessary before planting. Alfalfa requires high phosphorus and potassium levels and performs best on deep, fertile loam soils. It does not tolerate high water tables, heavy clay without drainage, or compacted soils. Soil testing and correction 6-12 months before planting is strongly recommended.
How long does alfalfa take to establish?
Alfalfa germinates in 7-10 days at soil temperatures above 65°F. Seedlings develop slowly for the first 60 days as the taproot establishes. First harvest is typically 60-90 days after planting. A full, productive stand is established by the second growing season. Do not graze or harvest new alfalfa stands until plants reach early bloom stage (approximately 10% of plants showing flowers) to ensure root carbohydrate reserves are adequate for regrowth.
How many cuttings of alfalfa can you get per year?
In USDA zones 4-6, expect 3-4 cuttings per year. In zones 7-8, 4-6 cuttings are possible. Harvest when alfalfa reaches early to mid-bloom (10-50% of plants flowering) for the best balance of yield and quality. Cutting intervals of 28-35 days maintain stand health. Always allow the last fall cutting 4-6 weeks before first expected frost so plants can rebuild root reserves for winter survival.
What is the seeding rate for alfalfa?
Seed alfalfa at 15-20 lbs per acre for pure stands, or 8-12 lbs per acre when mixed with grasses. For small plots, use approximately 0.5 lbs per 1,000 sq ft. Plant at 0.25-0.5 inch depth in a firm, well-prepared seedbed. Inoculate seed with Sinorhizobium meliloti (alfalfa-specific) inoculant before planting—this is critical for nitrogen fixation and cannot be substituted with clover inoculants.
How deep do alfalfa roots grow?
Alfalfa develops one of the deepest root systems of any cultivated crop. Taproots commonly reach 10-15 feet in well-drained soils and have been documented exceeding 20-25 feet. This extraordinary root depth provides exceptional drought tolerance, access to deep soil moisture and nutrients, and significant soil structure improvement. When old alfalfa stands are terminated, the decomposing root channels improve water infiltration and aeration for subsequent crops.
Can alfalfa be planted with grass for pasture?
Yes. Alfalfa-grass mixtures are among the most productive pasture systems available. Common companion grasses include orchardgrass, timothy, smooth bromegrass, and tall fescue. In mixed stands, alfalfa provides protein and nitrogen fixation while grasses provide energy (carbohydrates), ground cover, and reduced bloat risk. Plant alfalfa at 8-12 lbs per acre with grass at 4-8 lbs per acre. The grass component reduces (but does not eliminate) bloat risk compared to pure alfalfa.
