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.

One way of determining when it's a good idea to plant romaine lettuce is to examine the USDA zone info for Berthoud.

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 quite a bit earlier in the year because they do well in cold.

The earliest that you can plant romaine lettuce in Berthoud 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 fully mature. Starting your romaine lettuce indoors is a great way to get them started a little bit earlier.

Last Frost Date

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

Since the USDA zone info for Berthoud is not always accurate the actual date of last frost is different every year. Since half of the time in Berthoud you get a frost after April 15 be ready to protect your romaine lettuce if you have one of those late frosts.

USDA Zone Info for Berthoud

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 Berthoud

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