N.C. summer fruit won’t come without some winter work

Although North Carolina is in the middle of winter, some of your favorite summer fruits are getting attention on farms across the state. No, that’s not a reference to chocolate-covered strawberries you may have for Valentine’s Day. (If that’s a treat for you this February, your strawberries are likely coming from Florida or California unless you find a rare Carolina farmer taking a shot at greenhouse or hightunnel strawberries.)

The North Carolina strawberries you hope to enjoy in warmer weather are in the ground right now across the state. That’s also the case for strawberries on the state’s research stations. For example, at the Horticultural Crops Research Station in Castle Hayne, there are two research trials underway – one is breeding to compare common varieties with new varieties being developed, and the other trial is related to fungicides and disease control. Over the course of a few seasons, different sections of a strawberry plot are being treated with different fungicide options to see which works best, explained station superintendent John Garner.

Staff at Piedmont Research Station removing dead leaves from strawberry plots.

The strawberries on the station now were planted in October. They’ll continue growing through the winter and start blooming and producing fruit in warmer weather.

“The plant is alive but not producing right now,” Garner said. “So the biggest thing we’re doing is called ‘keeping them sanitized.’ We walk through the field and keep the bad stuff out and keep them clean basically.”

A couple of other N.C. summer favorites are also getting attention in the dead of winter. It’s time to prune peach trees and blueberry bushes throughout the state. Even muscadine grapes could be pruned now, but since they’re a fall fruit, there’s also some time to prune them into spring in summer.

Peaches and blueberries need to be pruned while they’re dormant before they begin to bud in warmer days. So farmers and their workers are out getting that work done during the frosty winter months. Garner said there are also blueberries on the station in Castle Hayne. Pruning is about all the staff of five does from Thanksgiving into February. Of course, there’s some time dedicated to keeping the strawberry patch clean too.

Frost protection will be the major concern as warmer days pop up before the threat of frost has completely passed. It’s that time of back-and-forth, freezing and warm days that we always see in North Carolina as winter turns to spring. Those are the days that present a challenge and concern.

“Once we get a little warmer and the strawberries set blossoms – when that cold weather comes back, we have to figure out if we’ll use row covers or irrigation water,” Garner said.

Spraying water from an irrigation system is also an option to cover and protect blueberries. For peaches, which don’t usually have irrigation systems, larger operations may use wind machines.
Garner explained that once the plants of strawberries, blueberries or peaches begin to bud during the first warm days of 2023, those buds could be damaged when a frost follows afterwards. Damaged or killed buds mean less fruit production later in the season. So high fruit yields can depend on avoiding early warm spells and managing any frosts that follow.

Frost protecting strawberry plants

Water sprayed on the plants builds up a protective layer. Damage to the budding fruit may not occur until temperatures are sustained for several hours around 28°, for example. Since the water freezes on the plant, it creates an ice barrier that’s closer to 32°, which protects the plant from colder temperatures.

It can be quite an undertaking, and ponds that provide water to irrigation systems could run dry. So there’s always a calculation about whether the cold spells will last longer than the water supply or whether there’s enough fruit budding to warrant protection.

“Once they start budding, we have to make the decision of whether there’s enough budding, or “fruit set,” to justify the manpower it would take to protect them,” Garner said. “Once you start, you’re committed to protection for the rest of the season. You’re not going to start today if you can’t protect next week.”

Since it takes a lot of water to run a frost protection system on several acres, the water supply and manpower is always a consideration. A particularly early warm spell may make it hard to sustain protection until the frost threat has passed in mid-April.

While many people aren’t thinking about all of this during cold weather, it’s something to remember when you’re enjoying delicious North Carolina fruit in spring and summer.