One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Zone 1b you can determine when it's possible to plant primroses by referring to the USDA zone info.

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 one of those plants that can tolerate quite a bit of cold weather you can plant them quite a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant primroses in Zone 1b is May. However, you really should wait until June if you don't want to take any chances.

The last month that you can plant primroses and expect a good harvest is probably July. If you wait any later than that and your primroses may not have a chance to really do well. Starting your primroses indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is June 15 in Zone 1b. In the coldest months of winter you can expect an average low temperature of -55°F.

Since the USDA zone info for Zone 1b may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Since half of the time in Zone 1b you get surprised by a frost after June 15 be ready to cover your primroses if you have a late frost.

USDA Zone Info for Zone 1b

Here is the info for USDA Zone 1b.

Average Date of Last Frost (spring)	June 15
Average Date of First Frost (fall)	July 15
Lowest Expected Low	-55°F
Highest Expected Low	-50°F

This means that on a really cold year, the coldest it will get is -55°F. On most years you should be prepared to experience lows near -50°F.

Plants to Grow in Zone 1b

You may be interested in your other planting guides for Zone 1b.