One of the first steps you take when you are figuring out your gardening schedule is find your 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.

By using the USDA zone info for Columbus you should be able to figure out when it's possible to plant calendula.

Planting Calendar for Calendula

Frost tolerance for calendula:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Calendula do well in moderate cold which means that you can plant them a little bit earlier than other frost tender plants.

The earliest that you can plant calendula 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 calendula and expect a good harvest is probably September. If you wait any later than that and your calendula may not have a chance to really do well. If you are starting your calendula indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

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

Remember that USDA zone info for Columbus is just an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Columbus you get a frost after April 15 so be sure to be ready to protect your calendula if you have a 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.