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.

One way of determining when it's a good idea to plant pentas is to refer to the USDA zone info for Joliet.

Planting Calendar for Pentas

Frost tolerance for pentas:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

It's probably not a good idea to plant pentas until after the last frost because they require warm weather.

The earliest that you can plant pentas in Joliet is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant pentas and expect a good harvest is probably August. Any later than that and your pentas may not have a chance to really do well. Starting your pentas indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Joliet. You should expect an average low temperature of -15°F in the coldest months of winter.

Remember that USDA zone info for Joliet is an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Joliet it frosts late in the year after April 15 so always be ready to protect your pentas if you have a late frost.

USDA Zone Info for Joliet

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 Joliet

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