The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of making a decision about when to plant romaine lettuce is to refer to the USDA zone info for Aspen.

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 do well in cold which tells us that you can get them planted much earlier than more sensitive plants.

The earliest that you can plant romaine lettuce in Aspen 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. You probably don't want to wait any later than that or else your romaine lettuce may not have a chance to really do well. Starting your romaine lettuce indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Aspen the average date of last frost happens on April 15. You should expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Aspen may not be accurate from year to year the actual date of last frost changes from year to year. Since half of the time in Aspen you get surprised by a frost after April 15 be ready to protect your romaine lettuce in the event of a surprise late frost.

USDA Zone Info for Aspen

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 Aspen

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