WASHINGTON TOWNSHIP — While October brings people to farms for hayrides, pumpkin patches and other fall fun, for cranberry farmers nestled in South Jersey’s ice box, the Pine Barrens, October means protecting against frost, which can damage crops.
Bill Haines Jr., owner and CEO of Pine Island Cranberry in Washington Township, Burlington County, says compared with other cranberry growing regions in the United States — Wisconsin, New York and Massachusetts — New Jersey is one of the best.
“We have an acidic soil, and we have a large clean water supply,” Haines said.
However, its sandy soil, rural land and low elevation of the cranberry bogs also make New Jersey highly sensitive to having frost halt the growing season, or give a sluggish start.
According to the University of California, Davis, more economic losses occur due to freeze damage in the United States than any other weather-related hazard. New Jersey ranks third in the nation for cranberry production, the state reports. In 2014, Jersey cranberries were a $21.9 million industry, according to the U.S. Department of Agriculture.
However, when autumn arrives in South Jersey, the thought of frost sends a chill down the spine of growers before it even reaches crops.
“We worry about frost when almost no other farmer has to think about it because of how and where cranberries grow,” Haines said.
In business for 120 years, Pine Island Cranberry’s bogs have seen nearly every storm, snow, wind, sun and temperature that can come to South Jersey.
Cranberries are so sensitive due to how they grow. “Because they grow so low to the ground. On a frost night, cold air settles and goes to the lowest point,” Haines said.
Frost is the fuzzy layer of ice crystals that form on a cold object as water vapor in the air changes to solid ice. To get frost, you need cold air, which naturally sinks. The lower the air can sink, the more the temperatures drops. In the Pine Barrens, where sandy soil dominates the region, the process is only accelerated due to the sand producing wild temperature swings (think sand on a sunny, summer day).
“There will likely be several days this cold season where the state’s coldest temperature will be at a Pinelands station,” said Dave Robinson, the New Jersey state climatologist.
That means constantly monitoring the weather in the cranberry bogs, specifically at the surface, as typical weather stations stand about 6.5 feet high.
“I’ve seen 10 degrees difference between weather station and vine level,” Haines said.
To make sure the icy crystals don’t destroy the cranberries, farmers employ a sprinkler technique.
“On a frost night, it’s Matt Giberson, our manager of operations (monitoring the temperatures and protecting against frost). While his team is out starting pumps, etc., they’re all monitoring and communicating with each other throughout the night,” said Haines.
The sprinkler system coats cranberries with a layer of water. The reason is physics. Even though temperatures are below freezing at the surface, even when it’s above 32 at official weather stations, the ice that forms around the cranberry is a warming blanket. The physical process of turning water into ice releases ‘latent heat’, which then warms the cranberry inside of the ice.
Despite just being part of the Garden State, South Jersey has a wide variety of climates and the Pine Barrens are the coldest on autumn nights.
According to the National Oceanic Atmospheric Administration, Indian Mills, part of Shamong Township in Burlington County, experiences its first 36-degree night Sept. 27, on average. That is significantly earlier than the rest of South Jersey. Atlantic City International Airport, on the edge of suburbia in Egg Harbor Township, has it’s first on Oct. 11. Cape May has its two weeks later than that, on Oct. 27.
However, Haines said that during the fall, when the fruit is riper, they are more hearty.
“In October, we wait until it hits 28 degrees,” Haines said.
That makes late October prime time for a killing freeze, when the temperature reaches 28 degrees. In Indian Mills, that first happens on average Oct. 21, about two weeks earlier than Atlantic City airport (Nov. 2) and more than a full month earlier than Cape May (Nov. 25).
Last year, the last fall freeze warning for Burlington County was Oct. 22. Atlantic and Cape May counties had a freeze warning issued later, on Nov. 11, said Dean Iovino, meteorologist for the National Weather Service in Mount Holly.
Turning to this year, a frost advisory was issued for mainland Atlantic, mainland Ocean and all of Cumberland and Burlington counties Saturday. Multiple standard weather stations reached 32 or below in the Pine Barrens, meaning it was even colder at the surface.
Frost protection is “probably the most important thing we do,” Haines said. He added that the most attention is paid during the spring, when the crops are tender, but the fall matters, too.