Hard frost, freeze, light frost, killing frost, what do these all mean? When is my garden really dead and what does this mean for spring planting? Hint, just ask your bed of thriving November Kale if we've had a killing frost. Through my nonscientific research, it appears that a lot of gardeners give up on their garden way too early at the first October breeze. Check out our cheat sheet below and stop scratching your head!
FROST ADVISORY or LIGHT FROST
A Frost Advisory is issued when the predicted temperature is expected to fall to 36 degrees (F) degrees or lower in the next 3 to 30 hours during the growing season for just a few hours. Cover those delicate flowering plants with a sheet overnight. Rumor has it that Kale flavor will improve after a light frost. Keep the soil moist by watering your plants the day a frost is predicted.
HARD FROST or HARD FREEZE
If the temperature is expected to fall below 28 degrees (F) this is considered a Hard Freeze. Because temperatures typically rise above freezing in the following days, cold-hardy plants will probably survive but may sustain leaf damage at these temperatures (eg. broccoli, kale, peas, carrots, parsnips your damn hostas). Continue to cover any thriving plants and water the day of a freeze.
KILLING FROST or SEVERE FREEZE
Shows over. Temperatures have reached below 24 degrees (F) or lower and you've had consecutive nights of below freezing temperatures. Most plants will experience heavy damage and die. Get out the wool blankets and check-in with your neglected indoor Succulents.
LAST FROST (SPRING)
Now for the good news! Mark your calendars as most early spring plantings can happen 4 to 6 weeks before the last frost date in your area. Don't miss out on early spring plantings such as broccoli, peas, beats, carrots, onions, potatoes and many types of greens. This also means starting those seeds indoors 4-6 weeks before you are able to get planting outdoors. For zones 4 & 5 (Minnesota+Wisconsin) the last frost is usually the end of April or May. But pay attention to the forecast, with climate change and El Niño the weather this year is totally unpredictable.