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 Gaithersburg you can determine when it's the best time to plant rosemary by using the USDA zone info.

Planting Calendar for Rosemary

Frost tolerance for rosemary:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Since rosemary do well in cold you can plant them earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant rosemary in Gaithersburg 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 rosemary and expect a good harvest is probably September. Any later than that and your rosemary may not have a chance to grow to maturity. You can get started a little bit earlier by starting your rosemary indoors.

Last Frost Date

On average the last frost has passed is on April 15 in Gaithersburg. In the coldest months of winter you can expect an average low temperature of 0°F.

Remember that the actual date of last frost is an average because it is based on the USDA zone info for Gaithersburg and it is different every year. Since half of the time in Gaithersburg last frost occurs after April 15 be ready to cover your rosemary if you have a surprise late frost.

USDA Zone Info for Gaithersburg

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 Gaithersburg

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