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.

It's possible to figure out when it's the best time to plant cosmos by using the USDA zone info for Nashua.

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 a tiny bit of cold which means that you can plant them just a tiny bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant cosmos in Nashua 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. If you wait any later than that and your cosmos may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your cosmos indoors.

Last Frost Date

On average the last frost has passed is on April 15 in Nashua. In the coldest months of winter you can expect an average low temperature of -15°F.

Keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Nashua and it changes from year to year. Since half of the time in Nashua you get a frost after April 15 be ready to cover your cosmos if you have a late frost.

USDA Zone Info for Nashua

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 Nashua

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