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

A common way of determining when to plant calibrachoa is to consult the USDA zone info for Hillsborough.

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 ok in very little cold which tells us that you can plant them a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant calibrachoa in Hillsborough 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 calibrachoa and expect a good harvest is probably August. If you wait any later than that and your calibrachoa may not have a chance to really do well. If you are starting your calibrachoa indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Hillsborough. You should expect an average low temperature of 5°F in the coldest months of winter.

Since the USDA zone info for Hillsborough is just an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Hillsborough you get a frost after April 15 be ready to cover your calibrachoa if you have one of those late frosts.

USDA Zone Info for Hillsborough

Here is the info for USDA Zone 7b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	5°F
Highest Expected Low	10°F

This means that on a really cold year, the coldest it will get is 5°F. On most years you should be prepared to experience lows near 10°F.

Plants to Grow in Hillsborough

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