Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

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

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 well in very little cold which tells us that you can plant them a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant petunias in Grayslake 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 grow to maturity. If you are starting your petunias indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Grayslake the average date of last frost happens on April 15. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Grayslake may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in Grayslake last frost occurs after April 15 so always be ready to protect your petunias if you have one of those late frosts.

USDA Zone Info for Grayslake

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 Grayslake

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