One of the best tools that you have as gardeners to help us estimate 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.

The USDA zone info for Rolla should be used to estimate when it's a good idea to plant petunias.

Planting Calendar for Petunias

Frost tolerance for petunias:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Petunias do ok in moderate cold which means that you can get them planted just a bit earlier than plants that are more sensitive to the cold.

The earliest that you can plant petunias in Rolla 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 petunias and expect a good harvest is probably August. Any later than that and your petunias may not have a chance to fully mature. Starting your petunias indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Rolla the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -5°F.

Just be sure to remember that USDA zone info for Rolla is an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Rolla you get a frost after April 15 so just be sure to be ready to cover your petunias if you have a late frost.

USDA Zone Info for Rolla

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 Rolla

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