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

You should be able to figure out when to plant diascia by checking out the USDA zone info for Princeton.

Planting Calendar for Diascia

Frost tolerance for diascia:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

You can plant diascia a bit earlier in the year because they are moderately cold tolerant.

The earliest that you can plant diascia in Princeton is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant diascia and expect a good harvest is probably August. You probably don't want to wait any later than that or else your diascia may not have a chance to really do well. If you are starting your diascia indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Princeton. You can expect an average low temperature of -30°F in the coldest months of winter.

Since the USDA zone info for Princeton may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Since half of the time in Princeton last frost occurs after May 15 be ready to cover your diascia in the event of one of those late frosts.

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.