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.

In Harvard you can determine when it's possible to plant calliopsis by using the USDA zone info.

Planting Calendar for Calliopsis

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

Since calliopsis do not do well in cold weather it's necessary to wait until after the last frost before you can plant them.

The earliest that you can plant calliopsis in Harvard is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant calliopsis and expect a good harvest is probably August. You probably don't want to wait any later than that or else your calliopsis may not have a chance to fully mature. If you are starting your calliopsis indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Harvard the average date of last frost happens on April 15. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Harvard is just an average the actual date of last frost is different every year. Half of the time in Harvard you get surprised by a frost after April 15 so be sure to be ready to cover your calliopsis in the event of one of those late frosts.

USDA Zone Info for Harvard

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 Harvard

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