The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By using the USDA zone info for Stewartville it's possible to estimate when it's the best time 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.

You can plant calendula just a bit earlier in the year because they are one of those plants that can tolerate a little bit of cold weather.

The earliest that you can plant calendula in Stewartville is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant calendula and expect a good harvest is probably August. 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 few weeks earlier.

Last Frost Date

In Stewartville the average date of last frost happens on May 15. You should expect an average low temperature of -25°F in the coldest months of winter.

Since the USDA zone info for Stewartville is an average the actual date of last frost can change quite a bit from year to year. Half of the time in Stewartville there is a last frost after May 15 so always be ready to cover your calendula if you have a surprise late frost.

USDA Zone Info for Stewartville

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Stewartville

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