The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A common way of determining when to plant phlox is to examine the USDA zone info for River Grove.

Planting Calendar for Phlox

Frost tolerance for phlox:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Phlox are moderately cold tolerant which tells us that you can start planting them earlier than plants that are more sensitive to the cold.

The earliest that you can plant phlox in River Grove is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant phlox and expect a good harvest is probably September. If you wait any later than that and your phlox may not have a chance to really do well. You can get started a couple of weeks earlier by starting your phlox indoors.

Last Frost Date

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

Since the USDA zone info for River Grove may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Half of the time in River Grove there is a last frost after April 15 so always be ready to protect your phlox in the event of one of those late frosts.

USDA Zone Info for River Grove

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 River Grove

You may be interested in your other planting guides for River Grove.