Old hay bales are those spoiled by weather, mold, or are too old and nutrient-deficient for livestock consumption. Although unfit for feeding animals, these bales contain significant organic material that can be successfully repurposed. Repurposing this excess material transforms a potential waste product into a valuable resource, preventing accumulation and integrating the material back into the environment.
Decomposing Hay for Soil Enhancement
Spreading hay across garden beds allows it to break down, enriching the soil structure and nutrient content. Hay, made from grasses and legumes, contains more nitrogen and organic matter than straw, leading to faster decomposition. Used as a garden mulch, hay helps suppress weed growth, moderates soil temperature fluctuations, and retains moisture.
For sheet mulching or “lasagna gardening,” hay acts as a carbon layer that slowly composts in place. This process can be accelerated by layering the hay with nitrogen-rich materials like fresh grass clippings or manure. The carbon-to-nitrogen ratio is important for efficient breakdown, with hay providing the carbon and the added materials supplying the necessary nitrogen.
Traditional composting is highly effective when combining spoiled hay with a nitrogen source like animal manure. The material must be properly moistened and regularly turned to ensure aeration. This helps the pile reach thermophilic temperatures (131°F to 160°F), which break down the hay efficiently and neutralize any weed seeds present.
Utilizing Bales for Structural Purposes
The physical structure of intact bales offers a temporary, biodegradable solution for various structural needs. Bales can be strategically placed to form temporary borders for raised garden beds, offering a simple way to contain soil for the season. This approach, often used in bale gardening, allows the bales to slowly decompose, adding material directly to the planting area over time.
Hay bales are widely used for erosion control to manage water runoff and prevent soil loss. Placing bales along a slope or waterway slows the flow of water, trapping sediment and allowing water to filter through. Proper installation requires entrenching the bales a few inches into the ground and staking them securely.
In high-traffic areas prone to becoming muddy, unrolled hay can be spread as a temporary, stabilizing material. The hay covers the wet soil and mixes with the mud, creating a firmer surface for foot or light vehicle traffic. This covering controls the mud while slowly breaking down into the underlying soil.
Repurposing Hay as Animal Bedding
Hay that is no longer palatable for feed, but is not excessively moldy, can be repurposed as absorbent bedding for various livestock. For animals like cattle, goats, or sheep, old hay provides cushioning and insulation in stalls and shelters. Although less absorbent than straw, it is often readily available to those who already store hay.
Using moldy hay as bedding carries significant health risks, particularly for horses. When disturbed, mold spores and dust become airborne, triggering severe respiratory conditions such as Recurrent Airway Obstruction (“heaves”). Ensure that any hay used for bedding is dry and relatively free of visible mold to protect the animal’s respiratory health.
The bedding should be refreshed frequently, as hay decomposes quickly once soiled by urine and manure. This rapid breakdown can lead to odor and a less sanitary environment compared to straw bedding. For poultry or smaller animals, a thin layer of older hay can be used but must be monitored closely for moisture buildup.
Safe Disposal of Contaminated or Unusable Hay
In cases where hay is severely spoiled or treated with persistent herbicides, reuse is ill-advised. Certain herbicides, like aminopyralid or clopyralid, persist through the digestive tract of animals and remain active after composting. Using contaminated hay or manure can destroy sensitive garden plants and vegetables for several years.
If herbicide contamination is suspected, the hay should not be used in compost or garden beds. A simple bioassay, such as planting sensitive indicator crops like peas or beans in a small sample, should be performed. For material too contaminated or too abundant to repurpose, safe disposal options must be considered.
Local regulations should be consulted regarding the controlled burning of spoiled hay, which effectively eliminates the material while respecting environmental laws. Alternatively, the contaminated hay may be spread thinly over non-sensitive areas, such as grass pastures or hayfields. This allows for slow degradation without affecting broadleaf plants.