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.

A way of estimating when it's a good idea to plant calendula is to look at the USDA zone info for Plover.

Planting Calendar for Calendula

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

Calendula do ok in mild cold which tells us that you can plant them a little bit earlier in the year than more sensitive plants.

The earliest that you can plant calendula in Plover 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. Any later than that and your calendula may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your calendula indoors.

Last Frost Date

The average date of last frost is May 15 in Plover. It might get as low as -25°F during the coldest months of winter.

Since the USDA zone info for Plover may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Half of the time in Plover you get surprised by a frost after May 15 so be sure to be ready to cover your calendula if you have one of those late frosts.

USDA Zone Info for Plover

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 Plover

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