One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You should be able to figure out when it's possible to plant iceberg lettuce by looking at the USDA zone info for Waterloo.

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.

Iceberg lettuce can survive in a tiny bit of cold which tells us that you can plant them a bit earlier in the year than other frost tender plants.

The earliest that you can plant iceberg lettuce in Waterloo is March. However, you really should wait until April 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 really do well. You can get started a few weeks earlier by starting your iceberg lettuce indoors.

Last Frost Date

The average date of last frost is April 15 in Waterloo. In the coldest months of winter you should expect an average low temperature of -20°F.

Since the USDA zone info for Waterloo is an average the actual date of last frost can change quite a bit from year to year. Half of the time in Waterloo you get a frost after April 15 so make sure that you are ready to protect your iceberg lettuce in the event of a late frost.

USDA Zone Info for Waterloo

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Waterloo

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