One of the best tools that you have as gardeners to help us estimate your gardening schedule is the 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.

In Rockville you can figure out when you can 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 start planting them much earlier than plants that are more sensitive to the cold.

The earliest that you can plant romaine lettuce in Rockville 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. If you wait any later than that and your romaine lettuce may not have a chance to fully mature. You can get started a little bit earlier by starting your romaine lettuce indoors.

Last Frost Date

The average date of last frost is April 15 in Rockville. In the coldest months of winter you should expect an average low temperature of 0°F.

Remember that USDA zone info for Rockville is not always accurate and the actual date of last frost can change quite a bit from year to year. Since half of the time in Rockville you get surprised by a frost after April 15 be ready to cover your romaine lettuce if you have a surprise late frost.

USDA Zone Info for Rockville

Here is the info for USDA Zone 7a.

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

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

Plants to Grow in Rockville

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