One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first opportunity to plant primula in Columbus can be determined 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 one of those plants that can tolerate quite a bit of cold weather you can plant them quite a bit earlier in the year than more sensitive plants.

The earliest that you can plant primula in Columbus 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 fully mature. You can get started a little bit earlier by starting your primula indoors.

Last Frost Date

On average the last frost is on April 15 in Columbus. You should expect an average low temperature of -20°F in the coldest months of winter.

Just be sure to remember that USDA zone info for Columbus is not always accurate and the actual date of last frost can change quite a bit from year to year. Half of the time in Columbus you get surprised by a frost after April 15 so always be ready to protect your primula in the event of a surprise late frost.

USDA Zone Info for Columbus

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 Columbus

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