Alfalfa, or Medicago sativa, is a legume forage valued for its high concentration of protein and calories, making it a popular feed component for horses. Achieving the high-quality, leaf-rich hay required for equine consumption demands precision at every stage of the growing process. This specialized approach, focusing on nutrient balance and safety, begins long before the seed is put into the ground. A tailored cultivation plan ensures the resulting hay is both palatable and meets the specific health needs of horses.
Preparing the Location and Soil
Growing high-quality alfalfa requires optimizing the soil environment, as the plant thrives in deep, well-draining soil that supports its extensive taproot system. A comprehensive soil test is necessary to determine the existing nutrient profile and acidity. Alfalfa requires a slightly alkaline soil, ideally between pH 6.5 and 7.5, which maximizes nutrient uptake and supports the symbiotic bacteria needed for nitrogen fixation.
If the soil test indicates acidity, agricultural lime must be applied four to twelve months prior to seeding, as its neutralizing effect is slow. The plant has a high demand for potassium and phosphorus, despite being a nitrogen-fixing legume. Phosphorus is necessary for vigorous seedling establishment, while potassium is linked to the stand’s longevity and winter hardiness. Perennial weeds, such as quackgrass, must be controlled before planting because young alfalfa plants are poor competitors.
Seeding and Initial Growth
The timing of planting significantly impacts the quality and texture of the resulting hay. Late summer planting is often preferred over spring planting because it results in finer stems and faces less competition from annual weeds. This timing allows the alfalfa crown to establish before the first killing frost, setting the stage for a productive first cutting the following year. For horse-grade hay, a slightly higher seeding rate (20 to 25 pounds per acre) is recommended to encourage competition among seedlings and produce desirable fine stems.
Alfalfa seed must be inoculated with the correct strain of Rhizobium meliloti bacteria, which allows the plant to convert atmospheric nitrogen into a usable form. Although many seeds are pre-inoculated, the bacteria are sensitive to sunlight and heat. Planting should be done immediately after inoculation, placing the seed shallowly in a firm seedbed. A seeding depth of 1/4 to 1/2 inch is correct for medium to fine-textured soils, with slightly deeper placement acceptable in sandy soils.
Initial soil moisture management is crucial for seedling survival until the deep taproot develops. A firm seedbed, achieved through cultipacking or using press wheels, ensures excellent seed-to-soil contact for moisture absorption. It is best to plant into moist soil, or when rain is highly probable. A small amount of moisture can germinate the seed but quickly lead to desiccation if dry weather follows. Once established, the young stand benefits from deep, infrequent watering to encourage downward root growth.
Ongoing Care and Pest Management
Once the stand is established, maintenance focuses on promoting a dense, healthy crop that naturally outcompetes weeds and resists pests. Because of the nitrogen-fixing relationship with Rhizobium bacteria, little to no nitrogen fertilizer is required. However, potassium and phosphorus levels must be monitored and maintained based on annual soil tests. For irrigation, deep, less frequent watering is more effective than shallow, daily sprinkles, which can promote surface weed growth.
Weed control in established stands relies heavily on cultural practices to avoid chemical residue in the final hay product. The most effective strategy is maintaining a vigorous, dense stand, which naturally shades out competing growth. Timely mowing is another tool, as cutting the alfalfa before weed seeds mature limits their spread. Avoiding irrigation immediately after a cutting helps suppress the germination of surface weeds that thrive on bare, moist soil.
For common pests like the alfalfa weevil, which damage the nutritious leaves, the most horse-safe control method is strategic timing of the first cutting. Harvesting the stand at the late bud stage, before the larvae cause significant damage, removes most of the pest population. This leads to their desiccation and starvation. Aphid populations are often kept in check through biological controls, as natural enemies like parasitic wasps and lady beetles maintain a healthy balance.
Harvesting for Safe Horse Feed
The harvest stage is the most important factor determining the quality and safety of alfalfa hay for horses. Alfalfa nutrient content declines, and stem fiber increases rapidly as the plant matures. To achieve the high-quality, digestible product preferred by equines, the crop should be cut at the late bud stage or early 10% bloom. This maturity level maximizes the leaf-to-stem ratio, resulting in hay that is high in protein and soft in texture.
After cutting, the curing process must be managed to dry the stems quickly while retaining the delicate leaves, which hold the majority of the nutritional value. Raking or turning the windrows should occur when the forage moisture is still high, around 40%, to prevent excessive leaf shatter. Using a roller conditioner, a mower that crimps the stems without crushing the leaves, helps speed up the drying process and minimizes the hay’s exposure to rain damage.
Avoiding mold and dust is paramount for equine respiratory health, requiring the hay to be baled within a specific moisture range. The ideal baling moisture for alfalfa is between 15 and 18% for small square bales, or lower for dense, large bales. Baling below 12% moisture leads to significant leaf loss. Baling above 20% risks dangerous heating, mold growth, and the creation of dust spores.
A serious safety concern, particularly during summer cuttings, is contamination by blister beetles. These insects contain cantharidin, a toxin deadly to horses, which is released when the beetle is crushed. Growers must avoid using hay crimpers during the second and third cuttings when blister beetles are most active, allowing the insects to escape the windrow naturally. If swarming is observed, harvesting should be delayed until the beetles disperse. The final hay product must be carefully inspected for any signs of the insects before being fed to horses.