One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's a good idea to estimate when to plant petunias by reviewing the USDA zone info for South Holland.

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 are barely cold tolerant which tells us that you can plant them slightly earlier than other plants that might not handle the cold.

The earliest that you can plant petunias in South Holland 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 couple of weeks earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in South Holland. You should expect an average low temperature of -10°F in the coldest months of winter.

Remember that USDA zone info for South Holland is an average and the actual date of last frost is different every year. Half of the time in South Holland it frosts late in the year after April 15 so make sure that you are ready to cover your petunias if you have one of those late frosts.

USDA Zone Info for South Holland

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 South Holland

You may be interested in your other planting guides for South Holland.