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 best time to plant cosmos in Lewistown can be determined by using the USDA zone info.

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 are one of those plants that can tolerate a tiny bit of cold weather which tells us that you can plant them slightly earlier than more sensitive plants.

The earliest that you can plant cosmos in Lewistown 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 cosmos and expect a good harvest is probably August. Any later than that and your cosmos may not have a chance to really do well. If you are starting your cosmos indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Lewistown the average date of last frost happens on April 15. You can expect an average low temperature of -5°F in the coldest months of winter.

Since the USDA zone info for Lewistown 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 Lewistown there is a last frost after April 15 so just be sure to be ready to cover your cosmos if you have a late frost.

USDA Zone Info for Lewistown

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Lewistown

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