One of the best tools that you have as gardeners to help us determine 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.

The USDA zone info for Lewiston can be reviewed to figure out when you can plant rosemary.

Planting Calendar for Rosemary

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

Rosemary do well in cold weather which means that you can plant them a lot earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant rosemary in Lewiston 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 fully mature. Starting your rosemary indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Lewiston. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Lewiston is not always accurate the actual date of last frost is different every year. Since half of the time in Lewiston it frosts late in the year after April 15 be ready to cover your rosemary if you have one of those late frosts.

USDA Zone Info for Lewiston

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 Lewiston

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