First hard frost coming Wednesday, while first snow falls Friday

As Wednesday brings Spokane’s first hard frost and Friday brings an early snow, 16-year-old Blake Bro is spending all day blowing out sprinkler systems and completing his online schoolwork at night.

Tom Bro, owner of T and B Sprinklers, and Blake, his son, have been slammed, Tom Bro said. They’ve been doing 25 sprinkler blowouts a day on the South Hill and more than 50 a day in Eagle Ridge on the weekends.

Wednesday night temperatures will dip into the low 20s, said Spokane National Weather Service meteorologist Robin Fox. After snow falls Friday, an even colder frost in the teens will creep through Saturday night.

“We’ll probably be waking up Saturday and seeing white,” Fox said. “Then Saturday, temps will creep up to middle to upper 30s and we’ll see that get wet on the roadways while shaded areas may hold on to the snow.”

Fox said it won’t accumulate enough to weigh down leaves and pull them off their branches. But the frost will interrupt the leaves’ natural cycle through changing colors, said Pat Munts, the small farms and urban agriculture coordinator for Washington State University Spokane County extension office.

“Here’s the other whammy: Once you get around 20-or-below temperatures, it tends to just flat-out freeze the leaves on the tree so they tend to stop turning color,” Munts said. “It doesn’t hurt the tree, but we’ll lose all of our color.”

She said gardeners should harvest “just about everything,” including hardy plants like cabbage and kale, ahead of the cold.

Bro said the first frosts will be short-lived enough that underground won’t freeze, but people should insulate the pipes that come out of the house into the ground and turn off the water.

“I’ve told 30, 40, 50 people today,” Bro said. “What I’ve been telling people to do is get a nice thick blanket and wrap that up with tape, give it a coat, so to speak.”

To protect tree branches from the weight of building snow, Munts recommends taking a long pole and lightly tapping the ends of the branches to knock snow off. It’s also time to plant any bulbs while the ground is soft enough to dig into and insulate temperature-sensitive plants like roses with a couple of feet of pine needles.

“Overall, the gardening season is over,” Munts said. “There comes a time where you just head inside and drink whatever you drink and get the fire going and watch Netflix.”