How to Grow Alfalfa 'Roundup Ready'
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Alfalfa 'Roundup Ready'
Medicago sativa var. transgenic
herbRoundup Ready alfalfa is a genetically modified perennial legume variety bred for herbicide tolerance to glyphosate (Roundup). It retains all the agronomic benefits of conventional alfalfa while allowing simplified weed management in production systems. This forage crop is primarily grown for livestock feed and soil improvement.
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Example Alfalfa 'Roundup Ready' timeline · Pittsburgh, PA (Zone 6b)
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Plant Alfalfa 'Roundup Ready'
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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Harvest Alfalfa 'Roundup Ready'
Around Oct 14≈ 180 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Alfalfa 'Roundup Ready' dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 3-8, with adapted varieties available for zones 2 and 9
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Germination & Seedling
3-4 weeksSeeds germinate in 5-10 days under warm conditions (65-75°F). Seedlings emerge with cotyledons and develop true leaves; root penetration begins.
Maintain consistent moisture but avoid waterlogging. Protect from heavy foot traffic and grazing. Monitor for seedling diseases in wet conditions. Delay first cutting until plants have 6-8 true leaves.
Vegetative Establishment
4-8 weeksPlants develop multiple stems, a stronger root system, and establish the characteristic compound leaves. Height increases to 6-12 inches; rhizobia nodules form on roots for nitrogen fixation.
Ensure adequate phosphorus and potassium. Avoid cutting or grazing in first season; allow full-year establishment for stand longevity. Use Roundup to control emerging weeds if needed.
Pre-Bloom to Flowering
2-3 weeksElongated flower buds appear; stems reach 20-36 inches tall. Flower clusters (purple, blue, yellow, or variegated depending on variety) develop. Nutritional quality is highest at late-bud to early-bloom stage.
Cut at bud stage or early bloom for optimal forage quality and yield. Glyphosate applications should complete 7 days before harvest. Allow 2-3 weeks between cuttings for regrowth.
Flowering & Seed Development
3-4 weeksFlowers in full bloom; small legume pods begin forming. If allowed to mature, seed pods develop with 1-8 seeds per pod. Plant becomes woody and fiber content increases.
For forage production, harvest before this stage to maintain palatability. If seed production is desired, allow full maturation (no grazing/cutting). Monitor for seed pod chalcid flies and other seed-eating insects.
Dormancy & Winter Rest
2-4 months depending on latitudeIn cold climates, plants enter winter dormancy with reduced growth. Regrowth potential is maintained by stored carbohydrates in roots and crowns. Minimal above-ground activity.
In fall, allow a final cutting 4-6 weeks before first frost to allow carbohydrate recovery. Avoid late cuttings that prevent dormancy preparation. Winter hardiness varies by variety; Roundup Ready types maintain typical cold tolerance of parent cultivars.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Monitor for yellow-striped adults in early spring. Biological control with parasitic wasp Bathyplectes curculionis. Timely cutting disrupts life cycle. Chemical control rarely needed with proper management.
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Select tolerant varieties. Monitor foliage for stippled yellowing. Predatory insects (ladybugs, lacewings) provide natural control. Avoid excessive nitrogen fertilization.
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Damage is usually cosmetic. Early cutting can reduce populations. Parasitic wasps naturally control larvae.
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Avoid insecticides that harm natural enemies. Scout during flowering. Cutting at late-bud stage minimizes flower bud damage.
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and
(fungal)
Ensure excellent drainage. Avoid waterlogging. Select resistant varieties if disease history exists. Crop rotation if severe.
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Maintain good air circulation and drainage. Remove infected plants. Avoid overwatering in spring. No chemical control is reliably effective.
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Timely harvest disrupts habitat. Biological control with Nosema locustae spores. Chemical control only if populations exceed economic threshold.
Uses
Livestock Forage
CulinaryAlfalfa hay is a premium protein source for cattle, horses, goats, and sheep, providing 15-22% crude protein depending on harvest stage. It is the most widely used legume forage in North American livestock feeding. [source]
Soil Nitrogen Enrichment
HouseholdAs a nitrogen-fixing legume, alfalfa reduces fertilizer dependency and improves soil fertility for subsequent crops. It can add 100-300 pounds of nitrogen per acre annually through root nodule symbiosis. [source]
Nutritional Supplement
MedicinalAlfalfa sprouts and leaf meal contain vitamins K, A, and E, plus minerals like calcium and iron. Historically used in folk medicine for digestive and joint health, though clinical evidence is limited. [source]
Weed Management Simplification
HouseholdRoundup Ready genetics allow glyphosate application for broad-spectrum weed control without harming the crop, reducing mechanical cultivation and labor. This is the primary agronomic advantage over conventional alfalfa. [source]
Pollinator Habitat
WildlifeAlfalfa flowers attract and support honeybees, native bees, and beneficial insects. Many beekeepers maintain alfalfa stands specifically for nectar and pollen production. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
Harvest at late-bud to early-bloom stage for optimal forage quality and digestibility. Cut 2-3 inches above ground to allow rapid regrowth. Typical schedule is 4-6 week intervals between cuttings in growing season, yielding 2-5 harvests annually depending on climate. In arid regions, irrigate 1-2 weeks before cutting. Allow 4-6 weeks of growth before first frost in fall for winter survival. Glyphosate can be applied 7+ days before harvest to control emerged weeds. Avoid cutting during bud break in early spring to ensure stand persistence.
Fun Facts
- 🌱 Alfalfa's scientific name 'Medicago sativa' comes from the Ancient Greek belief it was brought from Media (modern Iran), and 'sativa' means 'cultivated.' It is one of humanity's oldest cultivated crops, dated back to 1500 BCE.
- 🌱 Alfalfa roots can penetrate 10-20 feet deep, making it exceptionally drought-tolerant and allowing it to access water and nutrients far below the soil surface where shallow-rooted crops cannot.
- 🌱 Roundup Ready alfalfa was the first perennial forage crop approved for commercial GM use (USDA approval 2005) and remains one of the most widely adopted genetically modified crops in North America, with over 90% of U.S. alfalfa acreage now containing the trait.
Gardening Terms
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