Hay producers across the country are increasingly aware of the need to protect their alfalfa production from weather damage. The main goals when covering your hay piles are to dry the hay and prevent dry matter losses. As the demand and price of alfalfa increases, producers invest more effort in protecting their valuable hay. Traditionally protected alfalfa hay has been stored in (1) a hay barn or commodity shed or (2) under plastic tarps. A recent introduction (3) is the hay tarp (for example, the SupaCovaTM Breathable Tarp). It is important to know that poor quality tarps or improperly installed tarps may cause more damage to alfalfa hay than having no tarp or cover at all. Remember, achieving quality hay is a group effort from harvest to feedout, and it does require diligence and attention to detail from producers to ensure that forage quality does not become a limiting factor.

Hay Barn

A hay barn or commodity shed is considered to be a consistent highly effective method of storing hay. It provides the advantages of keeping water from the hay, and it allows for acceptable moisture loss if well stored and ventilated. However, one disadvantage of this method is that barns can be expensive to build and maintain as well as they need real estate in the farmyard to build.

Plastic Hay Tarps

Plastic hay tarps offer maximum flexibility. The advantage of plastic traps is they allow more protection while minimizing field transportation.  It allows hay to be stored in the field or in the bale yard until is ready to use or to be sold. A producer who tarps his hay has the flexibility to sell it when the market price and his price goals coincide. They are cheap, and keep water off the bale as well as being easy to manage. However, one disadvantage of plastic tarps is that often there are issues with trapping moisture as the bale dries out. Another disadvantage is they often suffer from exposure to Ultra-violet light which significantly reduces their service life.

Hay Tarp: A recent introduction into the Forage Producer’s Tool Box

Similar to a plastic tarp in usage, however hay tarps are made of a breathable material which allows moisture to leave the bale but also prevents precipitation from penetrating (it is similar to the commercial product “Goretex” in function; people who work outdoors appreciate this material for its ability to keep their feet dry in a durable light weight fabric boot). The advantages of this breathable tarp are: (1) allows passage of air and vapor (prevents mold); (2) provides excellent protection against rain (3) resistant to wind lifting; (4) maximum drying of damp straw after downpours; (5) extremely tear resistant (they have been shown to withstand strong winds); and (6) Ultra- violet light stable (which leads to a long service life). A disadvantage of this product is that it is more expensive than a traditional tarp (they can be up to five times the cost of a plastic tarp).

Get more out of your feed supply: Cover hay piles properly

Photo Source: Ed Zahn from Bruno Rimini Corp (2013)

The picture on the left side (A) shows alfalfa bales harvested at the same time but the bales in the front were left unprotected and showed signs of weathering, while those in the rear were protected with a breathable hay tarp. The picture on the right (B) shows the internal color of the alfalfa underneath the tarp.


After the forage has been properly covered, it is important to regularly inspect and repair the covered surfaces of the hay to maintain feed quality. In general, catching a damaged cover early can help minimize spoilage from excessive moisture. An annual evaluation of covering and feeding practices can help a livestock producer extend their hay inventory and feed higher quality forage all year long.


  1. Ball D, Bade D, Lacefield G, Martin N and Pinkerton B "Minimizing Losses in Hay Storage and Feeding". http://www.clemson.edu/psapublishing/PAGES/AGRO/Hay.pdf
  2. Hollin F (2009) Oxygen-Stopping Silage-Covering Systems Woks. Hay and Forage Grower. http://hayandforage.com/silage/0923-oxygen-stopping-silagecovering-system

Source: Karla Hernandez