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.

You should be able to figure out when it's the best time to plant calibrachoa by looking at the USDA zone info for Merrill.

Planting Calendar for Calibrachoa

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

Calibrachoa do well in a tiny bit of cold which tells us that you can plant them a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant calibrachoa in Merrill 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 calibrachoa and expect a good harvest is probably August. Any later than that and your calibrachoa may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your calibrachoa indoors.

Last Frost Date

In Merrill the average date of last frost happens on May 15. You can expect an average low temperature of -30°F in the coldest months of winter.

Since the USDA zone info for Merrill is just an average the actual date of last frost will vary from year to year. Half of the time in Merrill you get a frost after May 15 so just be sure to be ready to cover your calibrachoa in the event of a late frost.

USDA Zone Info for Merrill

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

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

Plants to Grow in Merrill

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