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

A common way of estimating when you can plant flower-of-an-hour is to look at the USDA zone info for Hampshire.

Planting Calendar for Flower-of-an-Hour

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

Since flower-of-an-hour are barely cold tolerant you can plant them slightly earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant flower-of-an-hour in Hampshire 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 flower-of-an-hour and expect a good harvest is probably August. You probably don't want to wait any later than that or else your flower-of-an-hour may not have a chance to grow to maturity. If you are starting your flower-of-an-hour indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Hampshire. In the coldest months of winter you should expect an average low temperature of -15°F.

Since the USDA zone info for Hampshire is not always accurate the actual date of last frost is different every year. Since half of the time in Hampshire there is a last frost after April 15 be ready to protect your flower-of-an-hour in the event of a late frost.

USDA Zone Info for Hampshire

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 Hampshire

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