The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first chance to plant romaine lettuce in Naperville can be determined by checking out the USDA zone info.

Planting Calendar for Romaine lettuce

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

Romaine lettuce are very cold tolerant which means that you can plant them much earlier than other plants that might not handle the cold.

The earliest that you can plant romaine lettuce in Naperville 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 romaine lettuce and expect a good harvest is probably September. You probably don't want to wait any later than that or else your romaine lettuce may not have a chance to grow to maturity. Starting your romaine lettuce indoors is a great way to get them started a few weeks earlier.

Last Frost Date

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

Since the USDA zone info for Naperville may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in Naperville there is a last frost after April 15 so make sure that you are ready to cover your romaine lettuce if you have a surprise late frost.

USDA Zone Info for Naperville

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 Naperville

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