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Women In Ag: Undercover Strawberries

What caused North Carolina strawberries to go undercover last weekend?

Last weekend Mother Nature sent North Carolina a cold front, causing temperatures to drop below freezing and the wind to whip across the state.

A number of crops were at risk for damage. Unseasonably warm weather caused apples, peaches, strawberries, and other fruits to bloom early. Even in a typical year, these crops would be blooming in April, and a heavy frost or freeze had the potential to wipe out the entire crop.

Why? From every bloom, a strawberry or apple or peach will grow. Flowers are sensitive to low temperatures. If the flower is damaged, fruit won’t develop.  

I live close enough to a strawberry farmer that I could see firsthand how he frost-protected his crop.

The first option is to use row covers. Large sheets of lightweight material are pulled over the rows, held in place by bags of rocks. The row covers provide a physical barrier and also help the soil lose less heat. Under cover, the flower’s temperature falls less quickly than if it wasn’t under cover. It reminds me of covering a baseball infield when it rains.

The second option, and the one that honestly fascinates me, is to use overhead irrigation. I’d never seen this until I started working with strawberry farmers. Tree fruit growers can also use this method.  

It works like this: As temperatures start to fall toward 32°F., overhead irrigation is turned on. Water covers the plants and as the liquid changes to ice, heat is released, insulating the flower. A field can be completely covered with ice, and the plants can escape unharmed.

The challenge is knowing when to turn on the water, when to turn off the water, and to keep it running constantly. Farmers must monitor irrigation equipment while it’s running, which means pulling an all-nighter. As you can imagine, irrigating in freezing temperatures can cause nozzles to clog or ice up. If plants don’t get enough water, they can be damaged.   

I talked to several strawberry farmers after the weekend, and there didn’t seem to be any damage. I visited two this week. If the beautiful red berries were any indication, we are going to have a good strawberry season this year in North Carolina. 

 

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