One of the first steps you take when you are making a decision about 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.

A way of getting a good idea when to plant cosmos is to examine the USDA zone info for Prior Lake.

Planting Calendar for Cosmos

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

Cosmos do ok in moderate cold which means that you can start planting them slightly earlier than more sensitive plants.

The earliest that you can plant cosmos in Prior Lake 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 cosmos and expect a good harvest is probably August. Any later than that and your cosmos may not have a chance to fully mature. You can get started a little bit earlier by starting your cosmos indoors.

Last Frost Date

In Prior Lake the average date of last frost happens on May 15. In the coldest months of winter you should expect an average low temperature of -25°F.

Since the USDA zone info for Prior Lake may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Half of the time in Prior Lake you get surprised by a frost after May 15 so just be sure to be ready to cover your cosmos in the event of a late frost.

USDA Zone Info for Prior Lake

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Prior Lake

You may be interested in your other planting guides for Prior Lake.