When Is It Safe to Plant Annuals in Minnesota?

As spring comes, many of us are eager to get outside and enjoy the warmer weather. One of the best parts about spring is getting our hands dirty in the garden. For those of us in Minnesota, that often means planting annual flowers. But when is the best time to plant them? Let’s find out!

Spring is a wonderful time to freshen up your landscaping with some beautiful annual flowers. However, it’s important to be aware of the risks associated with planting too early. In Minnesota, we can get a lot of late snowstorms and cold snaps well into May. If you plant your annuals too early and they incur damage from frost or freezing temperatures, they will not recover. It’s important to wait until all danger of frost has passed before planting.

For most plants you’ll want to consider planting them sometime in mid-May, but this is going to vary based on the plant and where you are in Minnesota.

Find Your Frost Date

The best way to determine when it’s safe to plant is to use a tool called the Frost Date Calculator. This tool uses historical data on average temperatures and calculates when the last expected frost will occur in your area.

Once you know this date, you can count back 6-8 weeks and start planting around that time, depending on the plant. The key is that you’ll want to start your planting calendar about a month or two before that frost date!

Some plants will want to be planted before the last frost. These hardy “cool weather plants” include cabbage, peas, broccoli, arugula, and kale.

Other annuals, like flowers should be started indoors, or in a greenhouse, and then go out after the final frost. Still others will have to wait until the soil temperate is higher, perhaps as high as 60 degrees consistently in order to see healthy growth.

With most of MN in zone 4 and the northern parts in zone 3, you have to watch the weather before you plant.

Frost Date Isn’t Perfect

Of course, even with the Frost Date Calculator, there is always some risk involved. The weather is unpredictable and things can change quickly. If you do choose to plant before the last expected frost date, be sure to keep an eye on the forecast and be prepared to cover your plants if necessary. At the first sign of frost, take measures to protect your plants so they can continue growing and blooming all season long!

Usually the final frost date in the Twin Cities area of MN is considered to be May 21st, but this might vary based on your area.

May Days Are Happy Days

Now that you know when it’s safe to plant annuals in Minnesota, it’s time to get out there and enjoy the gardening season! Be sure to use the Frost Date Calculator as a guide, but also keep an eye on the weather forecast so you can take steps to protect your plants if necessary. With a little planning and preparation, you can have a gorgeous garden that will bloom all season long!