One of the first steps you take when you are determining your gardening schedule is find your 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.

One way of figuring out when to plant four o' clock is to examine the USDA zone info for Mason City.

Planting Calendar for Four O' Clock

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

Four O' Clock are not cold tolerant which means that you have to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant four o' clock in Mason City 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 few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Mason City. You can expect an average low temperature of -20°F in the coldest months of winter.

Since the USDA zone info for Mason City is just an average the actual date of last frost is different every year. Since half of the time in Mason City there is a last frost after April 15 be ready to cover your four o' clock in the event of a late frost.

USDA Zone Info for Mason City

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Mason City

You may be interested in your other planting guides for Mason City.