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.

In Grinnell you can estimate when it's the best time to plant missouri primrose by looking at the USDA zone info.

Planting Calendar for Missouri Primrose

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

Since missouri primrose are one of those plants that can tolerate a little bit of cold weather you can plant them a little bit earlier in the year than more sensitive plants.

The earliest that you can plant missouri primrose in Grinnell 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 missouri primrose and expect a good harvest is probably September. Any later than that and your missouri primrose may not have a chance to fully mature. Starting your missouri primrose indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Grinnell the average date of last frost happens on April 15. You should expect an average low temperature of -20°F in the coldest months of winter.

It's important to remember that USDA zone info for Grinnell 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 Grinnell last frost occurs after April 15 so just be sure to be ready to protect your missouri primrose in the event of one of those late frosts.

USDA Zone Info for Grinnell

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 Grinnell

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