The USDA Zone info is a great tool for gardeners to help us determine 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.

It's possible to figure out when it's possible to plant primula by checking out the USDA zone info for Petersburg.

Planting Calendar for Primula

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

Primula tend to make it in a bit of cold which means that you can plant them quite a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant primula in Petersburg 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. If you wait any later than that and your primula may not have a chance to grow to maturity. If you are starting your primula indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Petersburg. You can expect an average low temperature of 5°F in the coldest months of winter.

Keep in mind that USDA zone info for Petersburg may not be accurate from year to year and the actual date of last frost is different every year. Half of the time in Petersburg you get surprised by a frost after April 15 so make sure that you are ready to protect your primula if you have one of those late frosts.

USDA Zone Info for Petersburg

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 Petersburg

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