One of the best tools that you have as gardeners to help us figure out your gardening schedule is the 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.

You should be able to determine when it's the best time to plant coleus by referring to the USDA zone info for Harvard.

Planting Calendar for Coleus

Frost tolerance for coleus:	Not tolerant of frost.
When to plant:	After the last frost.

Since coleus are not cold tolerant you really should wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant coleus 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 coleus and expect a good harvest is probably August. Any later than that and your coleus may not have a chance to grow to maturity. Starting your coleus indoors is a great way to get them started 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 can change quite a bit from year to year. Half of the time in Harvard last frost occurs after April 15 so be sure to be ready to cover your coleus 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.