One of the first steps you take when you are getting a good idea 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.

In Romeoville you can estimate when to plant four o' clock by using 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.

It's probably a bad idea to plant four o' clock until after the last frost because they are not cold tolerant.

The earliest that you can plant four o' clock in Romeoville 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. Any later than that and your four o' clock may not have a chance to fully mature. You can get started a few weeks earlier by starting your four o' clock indoors.

Last Frost Date

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

Remember that USDA zone info for Romeoville may not be accurate from year to year and the actual date of last frost is different every year. Since half of the time in Romeoville it frosts late in the year after April 15 be ready to cover your four o' clock in the event of a surprise late frost.

USDA Zone Info for Romeoville

Here is the info for USDA Zone 5b.

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

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Romeoville

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