Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Columbus can be used to determine when it's a good idea to plant primula.

Planting Calendar for Primula

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

Since primula do well in cold you can plant them earlier in the year than other plants that might not handle the cold.

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. If you wait any later than that and 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

In Columbus the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -10°F.

Just be sure to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Columbus and it changes from year to year. Half of the time in Columbus it frosts late in the year after April 15 so make sure that you are prepared to cover your primula if you have a late frost.

USDA Zone Info for Columbus

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 Columbus

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