Ask any farmer if they’d rather have a dry year or a wet year, and the answer is likely to be the same: Dry. “You can water, but if you have too much rain, you can’t take it away,” says Gary Mount of Terhune Orchards in Lawrenceville, one of several local farms that has been affected by drenching rains in recent weeks. The wet weather, which abated over the July 4th weekend while the heat continued, has had farmers scrambling to rescue crops in their most important planting season.

“There’s just too much rain,” Mr. Mount said last week. “Extra moisture encourages diseases on plants. The ability to deal with it is related to how long it goes on. It’s only been wet for two and a half weeks. If it goes on all next month, that will be hard to deal with. But usually, we go through a wet or dry spell, and then things change.”

The driving rains were also unwelcome at Great Road Farm in Skillman, which supplies some of the produce to the Witherspoon Street restaurant Agricola as well as farmers’ markets in West Windsor and Brooklyn.

“It could be a record in June for rainfall in New Jersey,” said farm manager Steve Tomlinson. “We’re struggling to get our succession planting in. We plant every two weeks, or at least every month, so we have a constant supply. Right now our greenhouse is backing up with plants that haven’t been able to get out into the field. Our tomatoes are looking pretty stressed.”

June actually did set a record as the wettest on record in New Jersey since 1895, according to information from the New Jersey state climatologist. The heavy rains damaged crops like blueberries, squash, and tomatoes.

“The only thing that doesn’t mind the water is sweet corn,” said Judee Deficcio, whose Pineland Farms in Hammonton supplies her stand at the Trenton Farmers’ Market. “We have sandy soil, which drains well but tends to wash away nutrients when there is that much water. Blueberries just keep absorbing water, and they get soft. The other problem with blueberries is that you don’t want to pick them when they’re wet. There were days when we’d pick for an hour or two instead of the usual 12. Also, you don’t want to pick in the extreme heat, and we’ve had plenty of that, too.”

Farmers know to prepare for heavy rains by planting raised beds. “This prevents the plants from getting over-saturated. It really helps us a lot,” said Mr. Mount. Planting varieties that are resistant to diseases caused by extra moisture is another form of insurance. More applications of fungicide can also help.

“It’s nobody’s favorite job, but you have to know that a rainy year requires more,” Mr. Mount said. “Most commercial farmers now use a monitoring system to help judge when they need more and when they don’t. In a wet year, more has to be used.”

The sweet cherries at Terhune are very susceptible to rain, but covering them to keep moisture out has saved this year’s crop. “It was a problem, but fortunately we had a way of dealing with it,” Mr. Mount said.

Ms. Deficcio watched an entire field of squash “just melt” in the rain, she said. Squash is one of the most easily damaged by saturation, and not just the summer varieties. “It may affect the pumpkin crop for the fall, because this is the time when pumpkin is planted,” she said. “There’s still some time to get them in, but we’ll have to see.”

Peaches, so prized in New Jersey toward the end of summer, should be okay, Ms. Deficcio added. Mr. Tomlinson said his Swiss chard, usually an easy crop, was showing signs of damage from the rains. There are concerns about tomatoes, which can be wiped out by a disease called late blight. “There are rumors that it’s going around,” he said. “It wiped out the entire tomato crop in 2009 for the organic farmers. That’s a huge money-maker. We are not certified organic, but we practice organic procedures.”

While the weather has done its damage, farmers aren’t ready to write off the summer of 2013 as a loss. “In New Jersey, we’re fortunate because we usually get an adequate amount of rain,” Mr. Mount said. “But too much is too much. So we do have to work extra hard. But if it doesn’t continue the way it’s been, we should be okay.”