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.

It's a good idea to estimate when it's a good idea to plant four o' clock by reviewing the USDA zone info for Ironwood.

Planting Calendar for Four O' Clock

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

Since four o' clock do not do well in cold weather it is necessary to wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant four o' clock in Ironwood is May. However, you really should wait until June 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. Any later than that and 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 couple of weeks earlier.

Last Frost Date

In Ironwood the average date of last frost happens on May 15. It might get as low as -30°F during the coldest months of winter.

Since the USDA zone info for Ironwood may not be accurate from year to year the actual date of last frost will vary from year to year. Since half of the time in Ironwood there is a last frost after May 15 be ready to cover your four o' clock in the event of one of those late frosts.

USDA Zone Info for Ironwood

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 Ironwood

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