The USDA Zone info is a great tool for gardeners to help us figure out 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.

The best time to plant four o' clock in Pittsburgh should be determined by checking out 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 has passed.

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

The earliest that you can plant four o' clock in Pittsburgh 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 really do well. Starting your four o' clock indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Pittsburgh. In the coldest months of winter you should expect an average low temperature of -5°F.

Since the USDA zone info for Pittsburgh may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Half of the time in Pittsburgh there is a last frost after April 15 so always be ready to cover your four o' clock in the event of one of those late frosts.

USDA Zone Info for Pittsburgh

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Pittsburgh

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