The Backyard

The Backyard

Tuesday, May 22, 2012

When Frost Bites Your Berries

In a perfect spring, these pictures would be filled with juicy, ripe strawberries. Most area farms are busy harvesting their strawberries - even with the unusually warm, dry, then cold spring we've had in central Pennsylvania. Mother nature decided spring was here in early March and many plants, including the strawberries, came out of dormancy too early.  Later in April, the temperatures plummeted to below freezing and fruit farmers worried about losing crops.  My berry patch was a victim.  The ground was unseasonably warm from March and with no snow cover this winter, I thought it wouldn't get cold enough to ruin the crops.  The weathermen teased us a couple times and said "freeze warning" yet the temperatures stayed in the 40's. How could we really know what the temp would be in the morning if the weathermen couldn't predict it?   I toyed with trying to cover the rows when the cold spells were predicted, but the old farmer in me thought it'll never get that cold.  I was mistaken.   I found an excellent technical article from the Ontario government on freeze protection for crops with information on how many degrees below freezing until the plant is threatened.  Just 1.1 Celsius ruins a bloom.  It was about 4 degrees below freezing on at least two of the mornings.  The majority of growers set up irrigation to actually coat the plants in ice to protect them from the freeze.  I recall seeing this method in Florida one year when visiting relatives.  There were fields and fields of ice-covered plants and water spraying everywhere.   I'm guessing that's what the farms in the area did judging by the beautiful berries they have for sale.  It's also possible their fields didn't get as cold as it did here.  Frosty morning temperatures vary greatly from farm to farm. I have a lot to learn on protecting berries from a freeze.   But not all is lost, after the initial flush of blooms, additional blossoms followed.  Those blooms did not freeze and we'll still have a partial crop in a couple weeks.  It'll be later than most, but berries nonetheless.

Also affected by the early warmth and late freezing are the wild black raspberries. We had a dry spell right after the warmth, so it's possible some of the damage here on these bushes is from dryness; but, comparing the buds to the strawberries, it appears the wild berries also were affected by the freeze.  

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