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 USDA zone info for Mchenry should be used to determine 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 are one of those plants that can tolerate a tiny bit of cold weather which tells us that you can get them planted just a bit earlier than other plants that might not handle the cold.

The earliest that you can plant petunias in Mchenry 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. If you wait any later than that and your petunias may not have a chance to fully mature. You can get started a little bit earlier by starting your petunias indoors.

Last Frost Date

The average date of last frost is April 15 in Mchenry. In the coldest months of winter you can expect an average low temperature of -15°F.

Keep in mind that USDA zone info for Mchenry is just an average and the actual date of last frost will vary from year to year. Since half of the time in Mchenry you get surprised by a frost after April 15 be ready to protect your petunias in the event of one of those late frosts.

USDA Zone Info for Mchenry

Here is the info for USDA Zone 5b.

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

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Mchenry

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