One of the best tools that you have as gardeners to help us determine 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.

The first chance to plant achillea in Crookston can be figured out by referring to 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 Crookston 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 achillea and expect a good harvest is probably August. If you wait any later than that and your achillea may not have a chance to fully mature. Starting your achillea indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Crookston the average date of last frost happens on May 15. You can expect an average low temperature of -30°F in the coldest months of winter.

Since the USDA zone info for Crookston is an average the actual date of last frost is different every year. Half of the time in Crookston it frosts late in the year after May 15 so make sure that you are ready to cover your achillea in the event of one of those late frosts.

USDA Zone Info for Crookston

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Crookston

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