Learn How to Plant and Grow Alfalfa

Understanding Alfalfa and Why It Matters

Alfalfa is a perennial legume plant that has been cultivated for thousands of years across the world. The plant gets its name from the Arabic word "al-fac-facah," which means "father of all foods." This nickname reflects alfalfa's remarkable nutritional profile and its importance in agriculture. Alfalfa typically grows between 1.5 to 3 feet tall and produces small purple, blue, yellow, or white flowers depending on the variety.

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The plant belongs to the Medicago sativa family and is known scientifically for its ability to fix nitrogen from the atmosphere into the soil. This means alfalfa naturally enriches soil without requiring synthetic nitrogen fertilizers, making it valuable for sustainable farming practices. According to the U.S. Department of Agriculture, alfalfa is grown on approximately 8.5 million acres across the United States, generating over $9 billion in annual value to the agricultural economy.

Alfalfa serves multiple purposes on farms and homesteads. Farmers primarily grow it as livestock feed because of its high protein content, typically ranging from 15 to 22 percent depending on harvest timing and growing conditions. Beyond animal feed, alfalfa can be used for human consumption in the form of sprouts, which are popular in salads and sandwiches. Some people also use alfalfa in traditional herbal remedies and nutritional supplements.

The plant thrives in temperate climates and can survive in diverse soil conditions, though it prefers well-drained soils with a pH between 6.5 and 7.5. Alfalfa's deep root system—sometimes extending 12 feet or more into the ground—allows it to access water and nutrients from lower soil layers, making it drought-tolerant once established. This characteristic makes alfalfa a practical choice for regions with irregular rainfall patterns.

Practical takeaway: Before planting alfalfa, understand that you're investing in a perennial crop that will produce for 4 to 8 years with proper management. Research your local climate and soil conditions to determine whether alfalfa matches your agricultural goals and environmental circumstances.

Preparing Your Soil and Site Selection

Successful alfalfa cultivation begins long before you place seeds in the ground. Soil preparation is one of the most critical steps in the planting process because alfalfa is sensitive to soil conditions and requires specific characteristics to thrive. Start by conducting a soil test through your county extension office or a private soil testing laboratory. This test will measure pH levels, nutrient content (nitrogen, phosphorus, potassium), organic matter percentage, and soil texture. Most testing services cost between $15 and $50 and provide detailed recommendations for soil amendments.

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Alfalfa grows best in soils with a pH between 6.5 and 7.5. If your soil is too acidic (below 6.5), you'll need to add agricultural lime to raise the pH. Application rates typically range from 1 to 3 tons per acre depending on how far below the target pH your soil tests. If your soil is too alkaline (above 7.5), sulfur can be applied, though this is less common in most regions. Plan to apply lime 6 to 12 months before planting to allow time for the material to work through the soil.

The physical structure of your soil also matters significantly. Alfalfa requires good drainage and will not tolerate waterlogged conditions. If your field has poor drainage, consider installing tile drainage systems or raising the bed elevation before planting. Compacted soils should be deep-tilled or loosened to at least 12 inches deep to allow the alfalfa's taproot to penetrate deeply. Many farmers use a moldboard plow or deep chisel plow to break up compacted layers.

Site selection involves more than just soil characteristics. Choose a location that receives full sunlight, ideally 6 to 8 hours of direct sun per day. Alfalfa grown in shaded areas will be weaker and more susceptible to disease. Avoid planting in low spots where water collects after heavy rain or near tree lines where shade and root competition from trees will inhibit growth. The field should also be accessible for equipment during planting and harvest.

Several weeks before planting, eliminate existing vegetation by plowing, tilling, or using herbicides appropriate for your region. Many farmers use a burn-down herbicide like glyphosate to kill existing weeds and grasses. After killing the vegetation, allow 1 to 2 weeks for decomposition before final seedbed preparation. Create a firm, fine seedbed by making multiple passes with a harrow or cultivator. The seedbed should be relatively smooth with small clods broken down to pea-sized pieces or smaller.

Practical takeaway: Invest in a soil test and allow 6 to 12 months before planting to make necessary pH and structural amendments. A well-prepared seedbed takes more time upfront but significantly improves germination rates and long-term plant establishment, potentially increasing your first-year yield by 20 to 40 percent.

Selecting Alfalfa Varieties and Obtaining Quality Seeds

Alfalfa comes in numerous varieties, each adapted to different climates, growing seasons, and intended uses. Understanding the available options helps you select the best variety for your specific location and goals. Varieties are generally classified by their fall dormancy rating, which indicates how the plant responds to decreasing day length and temperature as autumn approaches. This characteristic is important because it determines winter hardiness and the plant's ability to survive in cold climates.

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Fall dormancy ratings range from 1 to 11, with lower numbers indicating greater dormancy and higher cold tolerance. Varieties rated 1 to 3 are extremely dormant and suited for northern climates where winter temperatures regularly drop below minus 20 degrees Fahrenheit. Varieties rated 4 to 6 have moderate dormancy and are ideal for transitional climates with moderate winters. Varieties rated 7 to 11 are non-dormant or semi-dormant and perform better in southern regions with mild winters or in areas where multiple harvests per season are desired.

Beyond dormancy rating, alfalfa varieties differ in disease resistance. Some varieties offer resistance to common diseases like Verticillium wilt, Phytophthora root rot, and bacterial wilt. If your region has a history of specific diseases, select a variety with resistance to those pathogens. Seed suppliers can provide information about disease resistance packages included in their varieties. Additionally, some varieties are specifically bred for hay production, while others are better suited for grazing or silage production.

Purchase alfalfa seeds from reputable seed suppliers that provide germination test results and purity information. Quality seeds should have a germination rate of at least 85 percent and purity above 98 percent. Look for seed labeled with the variety name, fall dormancy rating, disease resistance package, and test date. Seeds typically cost between $40 and $100 per pound, depending on variety and whether inoculant is included. Most farmers plant at a rate of 15 to 20 pounds of seed per acre for hay production or 20 to 25 pounds per acre for pasture grazing, depending on soil type and expected growing conditions.

Many seed suppliers offer pre-inoculated seeds, which means the seeds have been coated with beneficial bacteria (Rhizobium meliloti) that form nodules on the roots and help the plant fix atmospheric nitrogen. If you purchase non-inoculated seeds, you can apply inoculant yourself, though pre-inoculated seeds are more convenient and ensure proper bacterial application. Store alfalfa seeds in cool, dry conditions—ideally between 40 and 50 degrees Fahrenheit with humidity below 50 percent. Properly stored seeds remain viable for 3 to 5 years, though germination rates decline over time.

Practical takeaway: Match your variety selection to your climate zone by using the fall dormancy rating system. Purchase seeds only from suppliers who provide germination rates and disease resistance information, and consider pre-inoculated seeds to support nitrogen fixation from the moment the plant emerges.

Planting Techniques and Timing

The timing of alfalfa planting depends on your geographic location and climate. In northern regions, spring planting from April through June is preferred because it gives seedlings time to establish before winter stress. In southern regions, fall planting from August through October allows seeds to germinate

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