It’s been a very warm and dry spring so far in Central PA, but it’s important to remember that our average last frost or freeze happens around April 21 every year. With the expected big drop in temperature, I drove down to Strites’ Orchard to find out what kind of impact that could have on vegetation here in the mid-state.
When looking for conditions that are harmful to plants and crops it’s not just the temperature, but also the duration of freezing temperatures and how far below freezing it gets.
“If it gets to below 32° for an hour, you’re not going to get much damage. But if it gets below there starting at midnight, and you have all morning, you’re going to have some significant damage,” says Jon Strite a farmer who manages the crops at Strites’.
Winds are a factor too. High winds prevent frost but can make a freeze worse. Like how humans react to the wind chill, a cold wind blowing across plants can suck the moisture right out of them and beat up tender young leaves.
Strite says, “We like to say you want to harden them off before setting them outside. You gotta keep in mind these plants are coming from a greenhouse where it’s a perfect environment, perfect temperature, no wind, out into the open where they’re just vulnerable to everything. So, you wanna get them as tough as possible before you plant them in your garden.”
The good news is with the recent warm and sunny afternoons, the ground is also warm, which will help in protecting your plants.
“Because the thermal heat that’s trapped within the ground will help to keep the surrounding air around those plants just a little bit warmer and keep them from freezing out,” Strite adds.
For the more sensitive outdoor plants and crops like tomatoes and peppers, it’s best to wait until consistent nights of no cooler than 50 degrees. If you have already planted them…make sure prior to a potential freeze that you water them well, cover them completely, and do it before sundown to prevent as much heat loss as possible.
And the good news for our plants and those who don’t like cold weather is that this cold shot is brief. By this weekend we’re back into the 60s, and next week, high temperatures will be back into the 70s.