Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Broomfield you can determine when it's a good idea to plant romaine lettuce by using 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 tells us that you can get them planted much earlier than more sensitive plants.

The earliest that you can plant romaine lettuce in Broomfield 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. If you are starting your romaine lettuce indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Broomfield. In the coldest months of winter you can expect an average low temperature of -10°F.

Remember that USDA zone info for Broomfield is an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in Broomfield you get a frost after April 15 be ready to protect your romaine lettuce in the event of a surprise late frost.

USDA Zone Info for Broomfield

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Broomfield

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