When to Plant Primula in Zone 1b

One of the first steps you take when you are making a decision about 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 figure out when it's possible to plant primula by reviewing the USDA zone info.


Planting Calendar for Primula

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

Primula are one of those plants that can tolerate quite a bit of cold weather which means that you can plant them much earlier than more sensitive plants.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant primula
Possibly ok, but a risky time to plant primula
Probably not a good time to plant primula

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

Last Frost Date

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

It's important to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Zone 1b and it can change quite a bit from year to year. Since half of the time in Zone 1b it frosts late in the year after June 15 be ready to cover your primula if you have one of those late frosts.

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.