One of the best tools that you have as gardeners to help us figure out 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.

By referring to the USDA zone info for Northbrook you should be able to estimate when it's the best time to plant lisianthus.

Planting Calendar for Lisianthus

Frost tolerance for lisianthus:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Lisianthus do not do well in cold weather which means that you need to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant lisianthus in Northbrook 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 lisianthus and expect a good harvest is probably August. You probably don't want to wait any later than that or else your lisianthus may not have a chance to fully mature. Starting your lisianthus indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Northbrook the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -15°F.

Since the USDA zone info for Northbrook is just an average the actual date of last frost is different every year. Half of the time in Northbrook last frost occurs after April 15 so just be sure to be ready to cover your lisianthus in the event of one of those late frosts.

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.