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.

The first chance to plant primroses in Lisle can be figured out by using the USDA zone info.

Planting Calendar for Primroses

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

Primroses can survive in pretty solid cold which means that you can plant them quite a bit earlier in the year than other frost tender plants.

The earliest that you can plant primroses in Lisle 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 primroses and expect a good harvest is probably September. You probably don't want to wait any later than that or else your primroses may not have a chance to fully mature. Starting your primroses 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 Lisle. You can expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Lisle is an average the actual date of last frost can change quite a bit from year to year. Half of the time in Lisle it frosts late in the year after April 15 so be sure to be ready to protect your primroses if you have a late frost.

USDA Zone Info for Lisle

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 Lisle

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