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.

You should be able to figure out when it's possible to plant primula by referring to the USDA zone info for Vandalia.

Planting Calendar for Primula

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

Primula can survive in quite a bit of cold which tells us that you can plant them quite a bit earlier in the year than more sensitive plants.

The earliest that you can plant primula in Vandalia 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 grow to maturity. Starting your primula indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost is on April 15 in Vandalia. It might get as low as -10°F during the coldest months of winter.

Keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Vandalia and it will vary from year to year. Half of the time in Vandalia there is a last frost after April 15 so be sure to be ready to cover your primula if you have a surprise late frost.

USDA Zone Info for Vandalia

Here is the info for USDA Zone 6a.

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

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

Plants to Grow in Vandalia

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