The USDA Zone info is a great tool for gardeners to help us estimate 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.

You can figure out when it's the best time to plant iceberg lettuce in Zone 4b by reviewing the USDA zone info.

Planting Calendar for Iceberg lettuce

Frost tolerance for iceberg lettuce:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since iceberg lettuce are barely cold tolerant you can plant them just a tiny bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant iceberg lettuce in Zone 4b 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 iceberg lettuce and expect a good harvest is probably August. You probably don't want to wait any later than that or else your iceberg lettuce may not have a chance to fully mature. You can get started a little bit earlier by starting your iceberg lettuce indoors.

Last Frost Date

On average the last frost is on May 15 in Zone 4b. It might get as low as -25°F during the coldest months of winter.

Always keep in mind that USDA zone info for Zone 4b is not always accurate and the actual date of last frost is different every year. Since half of the time in Zone 4b there is a last frost after May 15 be ready to protect your iceberg lettuce in the event of a surprise late frost.

USDA Zone Info for Zone 4b

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Zone 4b

You may be interested in your other planting guides for Zone 4b.