Knee-high curved plastic covered the corn in the fields during cooler weather, with temperatures dipping to 29 degrees at one point and frosting just the tips of the corn.
Each acre of corn cost Barnhart about $1,000 when it went in the ground. The gamble paid off and about 800 dozen bi-colored ears have been handpicked so far, Barnhart said.
Barnhart has seen the effects of the region's rainfall, pointing to one affected patch where the corn has noticeable variations in height. Barnhart and Steve Bogash, of the Penn State Cooperative Extension, said farmers actually prefer dry weather as long as they can rely on their water sources.
Barnhart, for instance, has pipes woven through the rows of corn on his 14 planted acres. The electric-powered pipes, which are under plastic, provide water directly to the roots from a nearby stream.
"Rain's just not that big of an issue," Bogash said.
Drier weather also decreases the likelihood of plant funguses developing and reduces the amount of pesticides needed.
The AccuWeather.com Agricultural Forecast Center in State College sent out a news release Wednesday saying that the corn harvest could be negatively affected by recent temperatures two to four degrees below normal. Bogash said that while cool temperatures might delay the harvest of some corn by a few days, plenty of ears should be available for the Fourth of July demand.
"Typically, our sweet corn starts showing up in quantity on the first of July or a little earlier," Bogash said.
He described Barnhart as "way ahead of the curve."
Farmers "are all trying to figure how to bring in that early corn that's affordable," Bogash said.
Bogash said the region's growers have benefited from the recent Salmonella scare with tomatoes and the fuel costs associated with transporting produce. He estimated that shipping tomatoes from California to this area can cost $10,000 to $15,000 a load.
"The beauty is that people are dying for our local stuff. Our local crop is extremely clean," Bogash said. "It's more of a level playing field now."
Before, states such as California and Arizona prospered due to long growing seasons and lower labor costs, Bogash said.
"Our local growers are doing quite well," he said, mentioning one Dauphin County, Pa., onion processor that is considering a switch to local onions versus those from California.
Barnhart takes his corn to several area Giant Food Stores and Martin's Food Markets. His preference, though, is to cut out the middleman and sell to consumers at his two roadside stands, one of which is at Trickling Springs Creamery on U.S. 11 south of Chambersburg.
The other stand is at Barnhart's farm off Social Island Road, not far from the Marion, Pa., exit off Interstate 81.
The National Agricultural Statistics Service reports that Pennsylvania harvests 14,200 acres of sweet corn a year.