One of the first steps you take when you are determining 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.

In Lewiston you can figure out when it's the best time to plant alyssum by reviewing the USDA zone info.

Planting Calendar for Alyssum

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

You can plant alyssum a lot earlier in the year because they are very cold tolerant.

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

Last Frost Date

On average the last frost has passed is on April 15 in Lewiston. You should expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Lewiston is not always accurate the actual date of last frost will vary from year to year. Half of the time in Lewiston it frosts late in the year after April 15 so always be ready to cover your alyssum in the event of a surprise late frost.

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.