One of the first steps you take when you are estimating your gardening schedule is find your 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.

The USDA zone info for Rockville should be reviewed to estimate when it's possible to plant iceberg lettuce.

Planting Calendar for Iceberg lettuce

Frost tolerance for iceberg lettuce:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

You can plant iceberg lettuce just a tiny bit earlier in the year because they are barely cold tolerant.

The earliest that you can plant iceberg lettuce in Rockville is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant iceberg lettuce and expect a good harvest is probably August. You probably don't want to wait any later than that or else your iceberg lettuce may not have a chance to grow to maturity. If you are starting your iceberg lettuce indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

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

Just be sure to remember that USDA zone info for Rockville is an average and the actual date of last frost changes from year to year. Half of the time in Rockville there is a last frost after April 15 so make sure that you are ready to cover your iceberg 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.