The USDA Zone info is a great tool for gardeners to help us determine 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 will be able to figure out when it's possible to plant romaine lettuce by reviewing the USDA zone info for Columbia.

Planting Calendar for Romaine lettuce

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

You can plant romaine lettuce earlier in the year because they are one of those plants that can tolerate quite a bit of cold weather.

The earliest that you can plant romaine lettuce in Columbia 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. Any later than that and your romaine lettuce may not have a chance to grow to maturity. If you are starting your romaine lettuce indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Columbia the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -5°F.

Since the USDA zone info for Columbia is an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Columbia it frosts late in the year after April 15 be ready to cover your romaine lettuce if you have a late frost.

USDA Zone Info for Columbia

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Columbia

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