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

In Charles City you can determine when to plant primula by using 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.

Since primula are very cold tolerant you can plant them much earlier in the year than more sensitive plants.

The earliest that you can plant primula in Charles City 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 fully mature. Starting your primula indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Charles City. You should expect an average low temperature of -20°F in the coldest months of winter.

Since the USDA zone info for Charles City is not always accurate the actual date of last frost changes from year to year. Half of the time in Charles City it frosts late in the year after April 15 so just be sure to be ready to cover your primula if you have one of those late frosts.

USDA Zone Info for Charles City

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Charles City

You may be interested in your other planting guides for Charles City.