One of the first steps you take when you are determining 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.

The USDA zone info for Grinnell can be used to estimate when it's the best time to plant monarda.

Planting Calendar for Monarda

Frost tolerance for monarda:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Monarda do ok in mild cold which means that you can plant them slightly earlier in the year than more sensitive plants.

The earliest that you can plant monarda in Grinnell 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 monarda and expect a good harvest is probably August. You probably don't want to wait any later than that or else your monarda may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your monarda indoors.

Last Frost Date

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

Always keep in mind that USDA zone info for Grinnell is just an average and the actual date of last frost changes from year to year. Since half of the time in Grinnell you get surprised by a frost after April 15 be ready to cover your monarda in the event of a surprise late frost.

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.