When to Plant Calibrachoa in Zone 4b

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

The best time to plant calibrachoa in Zone 4b should be estimated by using the USDA zone info.


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.

Since calibrachoa are barely cold tolerant you can plant them slightly earlier in the year than plants that are more sensitive to the cold.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant calibrachoa
Possibly ok, but a risky time to plant calibrachoa
Probably not a good time to plant calibrachoa

The earliest that you can plant calibrachoa in Zone 4b 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 fully mature. Starting your calibrachoa indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost is on May 15 in Zone 4b. In the coldest months of winter you should expect an average low temperature of -25°F.

Remember that the actual date of last frost is an average because it is based on the USDA zone info for Zone 4b and it will vary from year to year. Half of the time in Zone 4b last frost occurs after May 15 so always be ready to protect your calibrachoa in the event of a late frost.

USDA Zone Info for Zone 4b

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)May 15
Average Date of First Frost (fall)September 15
Lowest Expected Low-25°F
Highest Expected Low-20°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 -20°F.

Plants to Grow in Zone 4b

You may be interested in your other planting guides for Zone 4b.