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

By referring to the USDA zone info for Windsor it's a good idea to figure out when you can plant calliopsis.

Planting Calendar for Calliopsis

Frost tolerance for calliopsis:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Calliopsis are not cold tolerant which tells us that it's important to wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant calliopsis in Windsor 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 calliopsis and expect a good harvest is probably September. You probably don't want to wait any later than that or else your calliopsis may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your calliopsis indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on February 15 in Windsor. You can expect an average low temperature of 25°F in the coldest months of winter.

Since the USDA zone info for Windsor is just an average the actual date of last frost is different every year. Half of the time in Windsor it frosts late in the year after February 15 so be sure to be ready to protect your calliopsis if you have a surprise late frost.

USDA Zone Info for Windsor

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in Windsor

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