The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A way of making a decision about when it's a good idea to plant primula is to examine the USDA zone info for Alpena.

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 plants that are more sensitive to the cold.

The earliest that you can plant primula in Alpena 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 primula and expect a good harvest is probably September. You probably don't want to wait any later than that or else your primula may not have a chance to really do well. You can get started a few weeks earlier by starting your primula indoors.

Last Frost Date

On average the last frost is on April 15 in Alpena. In the coldest months of winter you can expect an average low temperature of -15°F.

Always keep in mind that USDA zone info for Alpena is just an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Alpena it frosts late in the year after April 15 so always be ready to cover your primula in the event of a late frost.

USDA Zone Info for Alpena

Here is the info for USDA Zone 5b.

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

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Alpena

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