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

One way of estimating when it's the best time to plant petunias is to check out the USDA zone info for Maryland Heights.

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 very little cold which means that you can plant them slightly earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant petunias in Maryland Heights 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 grow to maturity. Starting your petunias indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Maryland Heights the average date of last frost happens on April 15. You should expect an average low temperature of -10°F in the coldest months of winter.

It's important to remember that USDA zone info for Maryland Heights is an average and the actual date of last frost changes from year to year. Half of the time in Maryland Heights it frosts late in the year after April 15 so just be sure to be ready to cover your petunias in the event of a surprise late frost.

USDA Zone Info for Maryland Heights

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Maryland Heights

You may be interested in your other planting guides for Maryland Heights.