One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You will be able to figure out when it's the best time to plant primroses by checking out the USDA zone info for Duluth.

Planting Calendar for Primroses

Frost tolerance for primroses:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Since primroses are very cold tolerant you can plant them a lot earlier in the year than other frost tender plants.

The earliest that you can plant primroses in Duluth is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant primroses and expect a good harvest is probably September. Any later than that and your primroses may not have a chance to fully mature. If you are starting your primroses indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Duluth. In the coldest months of winter you can expect an average low temperature of 5°F.

It's important to remember that USDA zone info for Duluth is just 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 April 15 be ready to protect your primroses in the event of a surprise late frost.

USDA Zone Info for Duluth

Here is the info for USDA Zone 7b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	5°F
Highest Expected Low	10°F

This means that on a really cold year, the coldest it will get is 5°F. On most years you should be prepared to experience lows near 10°F.

Plants to Grow in Duluth

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