Hay is forage—most commonly grasses or legumes like alfalfa—that has been cut, dried, and stored for use as livestock feed when fresh pasture is unavailable. The hay-making process transforms this highly perishable crop, which can contain up to 80% water, into a stable, storable product. The goal is to reduce the moisture content significantly to prevent spoilage while preserving maximum nutrients, primarily protein and energy. This guide outlines the sequential steps necessary to achieve a high-quality finished product.
Determining Optimal Timing and Field Readiness
The single most important factor influencing hay quality is the plant’s stage of maturity at the time of cutting. As grasses and legumes mature, the content of lignin, a largely indigestible fiber component, increases, causing a sharp decline in protein and energy concentration. For grass hay, the ideal harvest time is typically at the late boot stage, just before the seed head fully emerges, while alfalfa is best cut at the bud to first-flower stage to maximize nutrient density.
A producer must secure a minimum window of three consecutive days of sunny, dry weather before any cutting begins, as the curing process depends heavily on solar energy and low humidity. Checking the long-range forecast is mandatory. Rain during curing leaches soluble nutrients from the cut forage. Before entering the field, a final check of all equipment ensures that machinery is properly calibrated and running smoothly, preventing costly delays.
Executing the Cut
The physical act of severing the standing crop is accomplished with specialized mowers, which are often paired with a conditioner to speed up the drying process. Disc mowers, which use small, high-speed rotating blades, are preferred for their speed and ability to handle heavy crops. Mower-conditioners, sometimes called haybines, use rollers or flails to crimp or abrade the plant’s stems immediately after cutting. This conditioning action is crucial because the thick stems dry much slower than the thin leaves, and crushing them helps the entire plant dry at a more uniform rate.
The cutting height must be set carefully to maximize yield while promoting rapid regrowth and preventing soil contamination. Leaving a stubble height of at least three to four inches allows the cut material to rest off the ground, promoting air circulation beneath the swath. The goal is to lay the cut material in a wide, flat swath—ideally covering 70% or more of the cut width—to maximize sun exposure and accelerate the initial moisture loss phase.
Curing, Tedding, and Raking
Curing is the field-drying process where the moisture content of the forage is reduced from its initial 75% to 80% down to a safe storage level, typically below 20%. Tedding, which uses spinning tines to lift and spread the cut hay, is often employed to flip the swath and expose the moister bottom layers to the sun and air. This action ensures uniform drying and is especially beneficial for heavy grass crops.
Tedding and subsequent raking must be timed precisely to avoid excessive leaf shatter, particularly with fragile legume hays like alfalfa, where the leaves hold the majority of the nutrients. The best practice is to rake the hay into windrows when its moisture content is still above 40%, because the leaves are flexible and less likely to break off. If the hay is already too dry, raking should be done in the early morning or late evening when dew or higher humidity temporarily raises the leaf moisture content. The final step before baling is using a rake to gather the uniformly dried hay from the wide swath into a narrow, continuous windrow.
Baling and Storing the Finished Hay
Baling is the final step, packaging the cured hay into dense, manageable units for storage and transportation. The moisture content at this stage is critical; hay that is too wet risks microbial growth, which generates heat and can lead to mold, spoilage, or spontaneous combustion. For small square bales, the moisture level should not exceed 18% to 20%, while denser large square or large round bales require a maximum of 15% to 18% moisture. Growers often use a handheld electronic moisture meter inserted into the windrow to verify this safe range.
Balers compress the hay into either rectangular square bales, which are easier to handle and stack in barns, or large cylindrical round bales, which are more suited for outdoor storage. Bale density must be sufficient to maintain shape but not so high that it traps moisture. Finished bales should be stored off the ground, often on rock pads or pallets, and ideally under cover to protect them from rain and weathering. If stored outside, round bales are typically placed tightly end-to-end and covered with a tarp to minimize nutrient loss.