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.

The USDA zone info for Northbrook can be read to determine when it's a good idea to plant violas.

Planting Calendar for Violas

Frost tolerance for violas:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Since violas are one of those plants that can tolerate quite a bit of cold weather you can plant them much earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant violas in Northbrook 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 violas and expect a good harvest is probably September. You probably don't want to wait any later than that or else your violas may not have a chance to really do well. If you are starting your violas indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Northbrook. You should expect an average low temperature of -15°F in the coldest months of winter.

Just be sure to remember that USDA zone info for Northbrook is not always accurate and the actual date of last frost will vary from year to year. Since half of the time in Northbrook last frost occurs after April 15 be ready to cover your violas if you have a late frost.

USDA Zone Info for Northbrook

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 Northbrook

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