The Art and Science of Making Good Hay

By Kathleen Hatt

Easy-to-handle square bales are stored in a dry barn at Grand View Farm in Canterbury, N.H.
Photos by Kathleen Hatt.

The old-timers had it right," says John Porter, professor emeritus and extension dairy specialist, University of New Hampshire Cooperative Extension. "They knew how good hay should feel when it is ready to put into the barn." As everyone in the Northeast who has tried to make hay this season knows, finding three consecutive days to cut, dry and bale good hay has not been easy. "Most other factors we can work around," says Porter. "But weather ..."

Why hay?

When weather is iffy, hay crop silage - cut, wilted, chopped and fermented legumes and roughage - is one way to go. But dry hay - grass, legumes or a grass/legume mix - has its value. It is important in meeting ruminants' nutritional requirements, and it also reduces the need for grain. The higher the forage quality, the smaller the amount of grain needed. Dry hay is also a practical way to raise young calves and small ruminants and to provide nutrition and roughage for horses.

What is good hay?

Hay is of the highest quality in the vegetative stage and before it is mature and headed out, when it is green and leafy, smells good, and is not coarse and hard. More leaves mean better hay. The protein content of good hay is ideally 18 to 20 percent, but Porter says that it's difficult to find this high-protein hay in New England.

Hay can be analyzed by either the wet chemistry method or by near infrared (NIR) analysis (available from Cornell University). Hay samples for testing should be collected from the core of the bale, not the outside. A core borer, available from farm supply stores, simplifies this task.

Tedding slows respiration in newly cut hay and decreases drying time.

When to hay

Capturing the nutrients in grass at just the right time so they will be available as feed over the winter months is both art and science. Hay quality decreases with maturity. "Haymaking should be timed to coincide with both the right stage of plant growth and the right weather," says Porter, whose experience with making hay extends back to his boyhood on a farm in New Hampshire's Connecticut Valley region. "Although conditions may not be right on these dates every year, shoot for May 15 in southern areas of the Northeast and May 25 farther north." This is the time when plants put most of their energy into vegetative growth and contain high concentrations of starches, proteins and minerals. For every day that harvest is delayed after the optimum date (May 20 to June 1), quality decreases. For a 1,400-pound cow:

Peak yields occur around July 4, but by then the period of peak nutritive value has passed. By July 4, plants are maturing and lignin content is increasing. Lignin traps nutrients within indigestible cell walls. Old-timers described hay cut around this time as being "stout and having some bottom to it."

Second, third and fourth cuttings tend to be leafy, and because they tend to be harvested in hotter weather, they are often easier to cure. Count on four or five weeks between cuttings.


Since harvesting takes three consecutive days of good weather, use a weather forecast rather than the date or time of day to determine the best two and a half to three-day interval. You can try mowing just after a rain, since the weather is then likely to be good for the next few days. Mowing in the morning gains more drying time. Mowing at the end of the day yields drier grass that contains a little more sugar.

To dry hay as quickly as possible, leave 3 to 4 inches of stubble on which to float hay above the ground, and be sure the cut swath is finely dispersed. The 3 to 4-inch stubble also helps regrowth of the next crop. Spread the windrows. Spreading thinly aids drying and reduces nutrient loss.

Mo Davison of Davison Farm in the Quaker District of Henniker, N.H., prepares to ted "first, second and thirdcut hay all in one" in mid-August 2013. Wet weather delayed this season's haying.


The purpose of tedding is to slow respiration in the newly cut hay and decrease drying time, so tedding should begin as soon as possible following mowing. Tedding can decrease the total drying time by as much as 30 to 40 percent. If the mowed swath is dry, hay cut early in the morning could be tedded that afternoon. A second tedding will speed drying. "To get hay dry, keep it moving," says Porter. Be aware, however, that substantial dry matter losses occur when very dry hay is tedded.


Raking should be done when hay is nearly dry, and generally not before 11 a.m. the day of baling, when the sun is near its daily peak and nighttime dew has dried. Hay is generally raked outward in clockwise passes around the field. Allow hay to dry an hour or two in the windrow before baling. "The outside windrow can be tricky, because it is often near a stone wall or in the shade, or both. If we were going to break equipment, this is where it happened," notes Porter. If possible, rake the outside windrow inward after the rest of the field is baled.


"There's no way around it: It takes a sunny, dry-air day to make good hay," says Porter. If hay is baled too early, moisture will be trapped and the bale will spoil. If hay is baled too late, dry leaves will shatter and break, lowering hay quality. Ready-to-bale hay will feel crisp but have no bunches of green grass. To test readiness, hold one end of a clump of hay in each hand and pull vigorously on each end. Stalks that break on the first pull are ready to bale. Stalks that require several pulls before breaking are too green. Electronic moisture testers can be used to confirm observations.

While the best moisture for baling is 15 to 18 percent, it is critical that moisture content be below 22 percent to avert the possibility of spontaneous combustion. Flammable gases are produced by a chemical reaction that begins when the internal temperature of hay reaches 130 degrees Fahrenheit. If the temperature continues to rise, the gases may ignite. The danger zone begins at 150 degrees Fahrenheit. At 175 degrees Fahrenheit, anticipate hot spots or fire pockets. At 185 degrees Fahrenheit, remove hay from the barn, with your local fire department on hand to control flames as air contacts the hot hay.

In mid-August 2013, Mo Davison of Davison Farm in the Quaker District of Henniker, N.H., heads toward a field to ted his first hay of the season. He describes the hay as "first, second and third cut all in one."

Whether making round or square bales, it is important to be sure to dry hay so it won't spoil. To avoid the possibility of moldy hay, don't make hay when it is overcast or sprinkling lightly. Preservatives are available, but for small operations the cost of equipment to apply them is prohibitive. Preservatives may also corrode equipment.

If the moisture content is high (50 to 60 percent), a round baler can be used to make balage, the round bale version of haylage. Dry hay in square bales is generally more manageable and marketable than large round bales. In New Hampshire, a season's hay averages 100 40-pound bales or 2 tons of hay per acre, but Porter says, "Well-fertilized fields can average over twice that amount."

Handling and storage

After bales have been picked up in the field, they are ready for storage. Bales, whether square or round, need to be under cover. A well-stacked pile of round bales can be tarped, but a tarp is not sufficient cover for stacked square bales, because it cannot be secured adequately enough to keep them dry. One solution is a hoop barn or other structure with easy equipment access designed specifically for hay storage.

In order to maintain quality, pay particular attention to how the bottom tier of bales is stored. Square bales on the ground should be stored on edge to prevent the baling twine from rotting. Round bales are usually stored on their sides to decrease capillary action. Even on a concrete floor, stored bales tend to pull moisture upward. When making a new concrete floor, use well-packed bank-run gravel covered by 6-mil plastic, poured concrete, and surface treatment of the concrete to minimize spoilage of the bottom layer of hay.

Expected Hay (or Equivalent in Hay Crop Silage) and Energy Intake from Forage Harvested at Various Dates Fed to a Cow Weighing 1,400 Pounds
Chart courtesy of John Porter.

Porter is experimenting with dirt flooring. He begins by covering dirt with a gravel base, then 6-mil plastic and fine crushed rock 2 inches deep. Atop the crushed rock, he builds a framed ridge floor using 2x4 or 2x6 lumber on edge, with narrow cracks between the top deck boards. He cautions against substituting pallets, which can be dangerous due to gaps and weak wood that can snap.

Preparing for the next crop

"To support the fields which grow good hay, establish a good soil testing and a good soil fertility program," says Porter. "You need to feed your fields." Begin the season with a fertilizer that has balanced nutrients. Between cuts, use nitrogen to kick-start growth. According to Porter, this is what good commercial farms do. Then, make sure all equipment has been maintained and is ready to go.

Having once lost a 2,000-pound round bale (and an hour's work) to the woods, Perry Dowst drives very slowly and carefully from Ed McCabe's field in Hillsborough, N.H., to the trailer he uses to transport hay back to his farm in Weare, N.H.

Tips for buying hay

If you purchase hay, especially on a regular basis, Porter advises establishing a relationship with one or two producers. Always order early. To save a little money, pick the hay up directly from the field. Quality producers will be happy to supply an analysis of hay - you just have to ask. "If you are new to buying hay, purchase second-crop," says Porter. "Second-crop hay is generally harvested during better weather and is less likely to be overmature."

Kathleen Hatt is a freelance writer and a frequent contributor to Farming. She resides in Henniker, N.H.