BELLINGHAM — As the first day of fall arrived Thursday, the first frost of the year is not far behind, potentially harming your hanging baskets as well as your garden.
The Farmers’ Almanac has predicted the first frost in four of Washington’s cities by finding the normal average first frost date.
According to the almanac, the first frost will be hitting Spokane first on Oct. 3. Olympia follows on Oct. 6, and Vancouver will likely get its first frost on Oct. 15. Seattle is expected to get its first frost about a month later on Nov. 17.
These dates are supposed to bring a light freeze between 29 to 32 degrees. This cold will kill tender plants such as cucumbers, pumpkins and tomatoes and have “little destructive effect” on other vegetation, according to the almanac.
Moderate freezes between 25 and 28 degrees bring heavy damage to blossoms, tender and semi-hardy plants, and have a destructive effect on most vegetation. Severe freezes under 24 degrees damage most plants, the almanac warns.
The Old Farmer’s Almanac, an almanac that started in 1792 and is annually updated, has predicted the first frost by city.
Here’s when the Old Farmer’s Almanac predicts your first frost:
Bellingham — Oct. 26.
Olympia — Oct. 6.
Tacoma — Nov. 7.
Kennewick — Oct. 25.
Pasco — Oct. 25.
Richland — Oct. 18.
Seattle — Nov. 10.
Spokane — Oct. 7.
Puyallup — Oct. 22.
Lynden — Oct. 16.
Ferndale — Oct. 23.
How to protect your plants from frost
The Old Farmer’s Almanac also offers advice to keep your plants safe from frost damage and provides a list of each plant’s critical low temperature when frost will damage plants.
Carrots, peas and potato tubers have a critical temperature of 28-30 degrees, where they will begin to be damaged from frosty weather. Tomatoes, sweet corn, sweet potatoes and watermelon have critical temperatures starting at 32 degrees and are considered tender plants.
The Old Farmer’s Almanac advises you to cover your garden with row covers made of non-woven polyester or with bed sheets, drop cloths or medium-weight fabrics to protect them from frost.
Local nurseries can also offer advice and resources to keep your plants safe in the cold. Paige Lanham, owner of Garden Spot Nursery in Bellingham, WA says one of the best ways to protect your plants is mulching.
“Making a 1-2” deep donut ring of mulch or compost around plants, especially those planted this year, can help protect them from the cold weather. This will both shelter them and feed the soil around them… Planting in the ground will keep a plant warmer than if it is planted in a pot, but if a plant is in a pot, they can be moved into the garage or close to the house during a cold snap,” Lanham wrote in an email to McClatchy.
Lanham also suggests wrapping a pot in bubble wrap to insulate it, and warns about the extra moisture winter frost and snow can bring:
“The wet ground in the PNW in the winter can be a killer as well, so making sure that you are planting in areas that have good drainage and adding some compost as you’re planting can help your plants survive as well,” Lanham wrote.
Here are a few ways you can prevent frost from damaging your plants and garden from Homes and Gardens:
• Do not keep potted plants outdoors during the winter months.
• Insulate your plants and garden with extra mulch before temperatures get colder.
• Move your tender plants into a sheltered area.
• Water plants in the mornings.
• Wrap larger plants and planters to keep them warm if you cannot move them inside.