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

The earliest that you can plant petunias in Winterset should be figured out by checking out the USDA zone info.

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.

You can plant petunias slightly earlier in the year because they are one of those plants that can tolerate a tiny bit of cold weather.

The earliest that you can plant petunias in Winterset 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. You probably don't want to wait any later than that or else your petunias may not have a chance to fully mature. Starting your petunias indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost is on April 15 in Winterset. In the coldest months of winter you should expect an average low temperature of -20°F.

Remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Winterset and it changes from year to year. Since half of the time in Winterset last frost occurs after April 15 be ready to cover your petunias if you have a surprise late frost.

USDA Zone Info for Winterset

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Winterset

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