Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A common way of getting a good idea when it's the best time to plant alyssum is to use the USDA zone info for Washington.

Planting Calendar for Alyssum

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

Since alyssum are one of those plants that can tolerate quite a bit of cold weather you can plant them a lot earlier in the year than more sensitive plants.

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

Last Frost Date

In Washington the average date of last frost happens on March 15. It might get as low as 10°F during the coldest months of winter.

Always keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Washington and it is different every year. Since half of the time in Washington you get a frost after March 15 be ready to cover your alyssum if you have a late frost.

USDA Zone Info for Washington

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

This means that on a really cold year, the coldest it will get is 10°F. On most years you should be prepared to experience lows near 15°F.

Plants to Grow in Washington

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