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.

You should be able to figure out when it's possible to plant four-o-clock flower by checking out the USDA zone info for Princeton.

Planting Calendar for Four-o-clock flower

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

It's probably not a good idea to plant four-o-clock flower until after the last frost because they require warm weather.

The earliest that you can plant four-o-clock flower in Princeton 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 flower and expect a good harvest is probably August. Any later than that and your four-o-clock flower may not have a chance to fully mature. If you are starting your four-o-clock flower indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

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

Always keep in mind that USDA zone info for Princeton is not always accurate and the actual date of last frost can change quite a bit from year to year. Half of the time in Princeton last frost occurs after May 15 so always be ready to cover your four-o-clock flower in the event of a surprise late frost.

USDA Zone Info for Princeton

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 Princeton

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