One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's possible to determine when to plant astilbe by looking at the USDA zone info for Fergus Falls.

Planting Calendar for Astilbe

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

Astilbe do well in very little cold which means that you can plant them a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant astilbe in Fergus Falls is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant astilbe and expect a good harvest is probably August. You probably don't want to wait any later than that or else your astilbe may not have a chance to fully mature. Starting your astilbe indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average all chance of frost has passed is on May 15 in Fergus Falls. In the coldest months of winter you should expect an average low temperature of -30°F.

Keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Fergus Falls and it will vary from year to year. Since half of the time in Fergus Falls you get surprised by a frost after May 15 be ready to protect your astilbe if you have a late frost.

USDA Zone Info for Fergus Falls

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 Fergus Falls

You may be interested in your other planting guides for Fergus Falls.