History of lime kilns in Monroe County

By Amy Leiser, Executive Director
Monroe County Historical Association

Autumn marks the end of Pennsylvania’s growing season, but it does not mean that a farmer’s work is done. For over two centuries, one of the most important autumn chores for Monroe County farmers has been the spreading of lime powder on their fields. The lime enriches and buffers the soil, preparing it for the next spring’s plantings. the 18th century, the Pennsylvania Germans discovered the value of lime as a soil amendment. According to Pennsylvania Agriculture and Country Life, lime was one of the most important components in Pennsylvania agriculture between 1790 and 1830.

Preparing lime often involved more work than spreading it. If a farmer did not have a limestone outcrop on his property, he would purchase large bushels of the rock from a local quarry. One bushel of lime weighed roughly 80 pounds and measured 1.25 cubic feet. Three Monroe County villages boasted large lime quarries and production: Saylorsburg; Kunkletown and Bossardsville. At one point in Monroe County’s history, Bossardsville was the center of the lime industry, where 2,000 bushels of lime were quarried daily. The average Pennsylvania quarry produced 200 bushels daily.

After quarrying the stone themselves or purchasing it, farmers would move the large bushel slabs to an area of their property for “burning” in a kiln. Many farmers had a lime kiln on their farms.These kilns were typically built out of flat local stones and were usually located along a steep hillside or in a wooded section of the property that was too difficult for growing crops. The large pieces of limestone would then be broken into smaller chunks, roughly eight inches in diameter, using sledgehammers. If the stones had a diameter greater than eight inches, the burning process took longer.

While each lime kiln is unique, they all generally have similar designs. The flat stones were stacked, using no mortar, in a cylindrical shape outside that formed an interior shaft which narrowed toward the bottom. A squared-off thick wall of stones surrounded the cylinder, giving the kiln a more boxy shape overall. Kilns usually reached a height of 10 to 20 feet. The top opening of the kiln measured between 8 and 12 feet across and tapered to about 3 to 4 feet across at the bottom. Inside the bottom of the kiln, a metal grate was placed to hold the wood needed for the burning process. Below the grate was a small central opening that would be used to collect the lime powder. This small opening was reached through a small door visible from the front exterior of the structure.

After the farmer had broken the lime into more manageable pieces, he would load the stones into the top of the kiln’s cylinder. Great care had to be taken to ensure that the rocks were not too tightly packed, as packing would restrict the circulation of air needed for the burning process. Initially, nearly all kilns were fueled by firewood; later ones occasionally burned coal. Having a wood-burning limestone kiln involved more work, but allowed for the lime to burn at a lower temperature, which resulted in product of better quality. The lime would burn for one week at temperatures ranging 1600 to 2100 degrees Fahrenheit. It also took about one week for the kiln to cool.

In the burning process, the stones would break down into a fine powder that fell through the grate and collected at the bottom of the kiln. The lime was then removed from the kiln using a small shovel or hoe and was hauled to the fields. In the fields, the lime was placed into small piles on the ground where it sat for several days until it was slaked, or spread, by hand. Usually, the lime was added to the soil along with manure. The manure would return nutrients to the soil, while the lime worked to buffer the soil’s pH. The process of burning the lime ensured that the powder was fine enough to dissolve into the soil where it binds to clay particles and neutralizes any acids present in the soil.

In addition to being a valuable soil amendment, lime had numerous other functions. It was used in the tanning industry and was often sold as white-wash for painting basements and barn walls. Interestingly, lime was also used in folk remedies. Lime, mixed with a variety of other ingredients, would be used to treat everything from burns, a sore throat, gangrene, and swelling to removing warts, eradicating moles from ones garden and fixing broken glass.

Whatever the use, for farming, for health, or for small fix-it jobs, the entire process of getting lime powder was time consuming. The entire process of obtaining the lime from a quarry and breaking it up into smaller stones, loading the pieces into a kiln, building a large fire that needed constant attention for one week, and spreading the powder by hand in farm fields was labor intensive. Today, a few lime kilns are still standing along Monroe County’s rural roads and are a testament to our local agricultural history.

Caption 1: A well-kept lime kiln in Pocono Township, Monroe County.
Caption 2: Drawing of a cross-section of a limekiln found in Pennsylvania Limekilns by Amos Long Jr. in the archives of the Monroe County Historical Association.