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

You should be able to figure out when it's possible to plant cosmos by using the USDA zone info for Riverton.

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 well in very little cold which means that you can plant them slightly earlier in the year than other frost tender plants.

The earliest that you can plant cosmos in Riverton 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 fully mature. You can get started a little bit earlier by starting your cosmos indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Riverton. It might get as low as 0°F during the coldest months of winter.

It's important to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Riverton and it will vary from year to year. Half of the time in Riverton there is a last frost after April 15 so always be ready to cover your cosmos in the event of one of those late frosts.

USDA Zone Info for Riverton

Here is the info for USDA Zone 7a.

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

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

Plants to Grow in Riverton

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