The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The best time to plant cosmos in Three Rivers should be figured out 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 do ok in moderate cold which means that you can get them planted just a bit earlier than more sensitive plants.

The earliest that you can plant cosmos in Three Rivers 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. You probably don't want to wait any later than that or else your cosmos may not have a chance to grow to maturity. Starting your cosmos indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Three Rivers. In the coldest months of winter you can expect an average low temperature of -15°F.

Since the USDA zone info for Three Rivers is not always accurate the actual date of last frost will vary from year to year. Since half of the time in Three Rivers it frosts late in the year after April 15 be ready to protect your cosmos if you have a surprise late frost.

USDA Zone Info for Three Rivers

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Three Rivers

You may be interested in your other planting guides for Three Rivers.