Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of figuring out when to plant flower-of-an-hour is to examine the USDA zone info for Duluth.

Planting Calendar for Flower-of-an-Hour

Frost tolerance for flower-of-an-hour:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

You can plant flower-of-an-hour slightly earlier in the year because they do ok in moderate cold.

The earliest that you can plant flower-of-an-hour in Duluth is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant flower-of-an-hour and expect a good harvest is probably August. You probably don't want to wait any later than that or else your flower-of-an-hour may not have a chance to fully mature. If you are starting your flower-of-an-hour indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Duluth the average date of last frost happens on May 15. It might get as low as -30°F during the coldest months of winter.

Just be sure to remember that USDA zone info for Duluth is an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in Duluth you get surprised by a frost after May 15 be ready to protect your flower-of-an-hour if you have a surprise late frost.

USDA Zone Info for Duluth

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Duluth

You may be interested in your other planting guides for Duluth.