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.

The best time to plant four o' clock in Port Huron should be determined by referring to the USDA zone info.

Planting Calendar for Four O' Clock

Frost tolerance for four o' clock:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Since four o' clock require warm weather you really should wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant four o' clock in Port Huron 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 four o' clock and expect a good harvest is probably August. You probably don't want to wait any later than that or else your four o' clock may not have a chance to fully mature. Starting your four o' clock indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Port Huron the average date of last frost happens on April 15. You can expect an average low temperature of -10°F in the coldest months of winter.

Remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Port Huron and it will vary from year to year. Since half of the time in Port Huron you get surprised by a frost after April 15 be ready to cover your four o' clock if you have a surprise late frost.

USDA Zone Info for Port Huron

Here is the info for USDA Zone 6a.

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

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

Plants to Grow in Port Huron

You may be interested in your other planting guides for Port Huron.