Paul Gross: Read this before you plant your tender annuals

We sometimes get frosts in May


DETROIT – Happy Mother’s Day weekend! Now that people have heard about the sunny weekend and warm week ahead, I’ve been hearing all sorts of chatter about people intending to do their planting this weekend.

If that’s your plan, I urge some caution: We sometimes get frosts in May. In fact, low spots in rural areas may even get a touch of frost this weekend.

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Look at the statistics

Let’s first dive into the statistics. Even though our long-term average lows right now are in the mid-40s (8 degrees Celsius), our daily record lows are in the upper-20s to low-30s (-2 to 0 degrees Celsius).

In fact, our latest frost ever was May 29th, 1966, and that was recorded at Metro Airport. It was likely colder across the northern half of the area.

Furthermore, we even had a record low of 36 degrees (2 degrees Celsius) on June 11th, 1972, which means there may have been some frost in some areas on that morning.

Yes, the forecast for the coming work week is warm, with no chance for frost. However, the long-range computer models suggest cooler weather for the week after that.

Now, I cannot tell you right now if it’ll be cold enough for frost at that point. All I’m saying is that I personally never plant until Memorial Day weekend, or the weekend before Memorial Day weekend if I don’t see any frost chances at that point.

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It’s not just about frost

And, also remember that it’s not just about frost -- when you transplant those little annuals into the ground, you want the soil temperature to be warm enough that the plant isn’t shocked by a sudden change to cold soil.

Having said all of this, remember that cooler-weather tolerant plants like pansies are just fine to plant. I’m referring to tender annuals, such as impatiens, petunias, etc.

Trust me: I know you’re itching to get out there and plant your annuals this weekend. I sure am! But I’m not going to do it.

Mother Nature has burned us too many times for me to plunk down $150 for flowers, and then potentially lose them. So proceed with caution this weekend! Pamper the mother(s) in your life and, if you MUST get some flowers into the ground because you have family coming over Sunday, perhaps consider beautiful pansies, which can handle whatever cold weather comes our way.

One final piece of advice if you’ll be spending lots of time outside this weekend: With afternoon highs mostly in the low-60s and a breeze making it feel a little cooler, the last thing you’ll be thinking about is sunscreen. But what I want you to remember is that the temperature has nothing to do with if you’ll get a sunburn or not (except for how much exposed skin you have).

The sun’s rays are the key and, right now, the sun’s rays are as strong as they will be around August 1st. You’ll burn as quickly this weekend as you would on Aug. 1 -- and probably even faster because you still have your “winter tan.” Please use sunscreen -- every burn you prevent lowers your chance of getting skin cancer.

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About the Author:

Local 4 meteorologist Paul Gross was born in Detroit and has spent his entire life and career right here in southeast Michigan. Paul has researched, written and produced eight half-hour documentaries for WDIV, as well as many science, historical and environmental stories.