The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You can determine when you can plant four o' clock in Ann Arbor by looking at the USDA zone info.

Planting Calendar for Four O' Clock

Frost tolerance for four o' clock:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

It's not a good idea to plant four o' clock until after the last frost because they do not do well in cold weather.

The earliest that you can plant four o' clock in Ann Arbor 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 grow to maturity. If you are starting your four o' clock indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Ann Arbor. It might get as low as -10°F during the coldest months of winter.

Since the USDA zone info for Ann Arbor may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in Ann Arbor you get surprised by a frost after April 15 so just be sure to be ready to cover your four o' clock in the event of a surprise late frost.

USDA Zone Info for Ann Arbor

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 Ann Arbor

You may be interested in your other planting guides for Ann Arbor.