One of the best tools that you have as gardeners to help us figure out 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.

You can estimate when to plant calendula in Oelwein by looking at the USDA zone info.

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 start planting them earlier than plants that are more sensitive to the cold.

The earliest that you can plant calendula in Oelwein 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. Any later than that and your calendula may not have a chance to really do well. Starting your calendula indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Oelwein. It might get as low as -20°F during the coldest months of winter.

Just be sure to remember that USDA zone info for Oelwein is an average and the actual date of last frost changes from year to year. Since half of the time in Oelwein you get surprised by a frost after April 15 be ready to protect your calendula if you have one of those late frosts.

USDA Zone Info for Oelwein

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 Oelwein

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