Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You can determine when you can plant achillea in Grinnell by looking at the USDA zone info.

Planting Calendar for Achillea

Frost tolerance for achillea:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

You can plant achillea much earlier in the year because they are very cold tolerant.

The earliest that you can plant achillea 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 achillea and expect a good harvest is probably September. You probably don't want to wait any later than that or else your achillea may not have a chance to really do well. If you are starting your achillea indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

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

Just be sure to remember that the actual date of last frost is an average because it is based on the USDA zone info for Grinnell and it can change quite a bit from year to year. Half of the time in Grinnell it frosts late in the year after April 15 so make sure that you are ready to protect your achillea 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.