Hay is forage, typically grasses or legumes, cut and dried to be stored as feed for livestock. Turning a field of green plants into stable, nutritious hay requires strict control over the plant’s moisture content throughout the harvesting process. Proper harvesting techniques directly determine the nutritional value of the final product, making timing and precision paramount.
Preparing for the Harvest
The decision to begin the hay harvest depends primarily on the plant’s stage of maturity. For cool-season grasses, the optimal time to cut is typically at the late boot stage, just before the seed head emerges. Harvesting at this point balances the maximum accumulation of digestible energy and protein with a reasonable yield, as nutritional quality declines rapidly once the plant begins to produce seeds.
Weather forecasting is a determining factor because the entire process requires a sustained period of dry conditions. Producers look for a window of at least three to five consecutive days of clear, warm, and sunny weather with low humidity. Rainfall after the crop is cut can leach out soluble nutrients, delay drying, and lead to mold development, severely reducing the hay’s feed quality. Calculating the potential yield and confirming the forecast are the final considerations before cutting.
Cutting the Crop
The first physical step is severing the crop from the field, often accomplished with a mower-conditioner. These machines cut the forage and immediately process it by running the material through rollers that crimp or crush the stems. This conditioning step is important because thick stems contain more moisture than the leaves and dry much slower. Crushing the stems allows them to dry at a rate closer to the leaves, speeding up the overall curing time.
The cutting height is an important consideration for both the current crop and the future health of the field. Leaving a stubble height of at least three to five inches promotes faster regrowth and allows air to circulate beneath the cut material. Farmers aim to lay the cut forage down in a wide, uniform swath, maximizing its exposure to solar radiation and airflow for rapid initial moisture loss.
Curing and Drying the Hay
The goal of curing is to reduce the initial moisture content from 70–80% down to a safe storage level, typically between 15 and 20%. To accelerate this process, a hay tedder is often used shortly after cutting to spread and fluff the material across the field. This mechanical action breaks up clumps and inverts the hay, ensuring all parts are exposed to the sun and air for uniform drying.
Once the hay is sufficiently dried, a rake gathers the material into long, continuous rows called windrows, sized for the baling equipment. Raking is ideally performed when the hay still has a moisture content around 35 to 40% to minimize the loss of delicate leaves, which are the most nutrient-dense part of the plant. If raked when too dry, the leaves shatter and fall to the ground, lowering the overall nutritional quality.
Accurate moisture testing is required before baling to prevent spoilage and dangerous conditions in storage. If the hay is baled too wet, microbial respiration generates heat, leading to mold growth and reducing digestibility. For hay baled above 25% moisture, internal heating can exceed 140 degrees Fahrenheit, carrying the risk of spontaneous combustion. Farmers use electronic moisture meters for precise readings or perform a quick hand test, such as the twist test, to check for sufficient dryness.
Baling and Storing the Finished Product
Baling packages the cured hay into a manageable form for transport and storage, and the choice of bale type depends on the operation. Small square bales, which are easier to handle manually, are typically baled at 20% moisture or less. Denser, larger bales, such as large squares or round bales, require a lower moisture content, often 15 to 18%. Bale density is important, as a tighter package sheds moisture better when stored outdoors.
Once packaged, the hay must be moved quickly to a storage location to protect it from weather and ground moisture. The best method for long-term preservation is stacking the bales inside a well-ventilated barn or shed. If outdoor storage is necessary, the bales should be placed on a raised surface, such as gravel or pallets, to prevent wicking moisture from the ground. Round bales are typically stored end-to-end to minimize the surface area exposed to precipitation.