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

In Spokane you can estimate when it's a good idea to plant alyssum by looking at 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.

Since alyssum are very cold tolerant you can plant them much earlier in the year than other frost tender plants.

The earliest that you can plant alyssum in Spokane 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. If you wait any later than that and your alyssum may not have a chance to fully mature. If you are starting your alyssum indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Spokane the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -5°F.

Keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Spokane and it can change quite a bit from year to year. Since half of the time in Spokane it frosts late in the year after April 15 be ready to protect your alyssum if you have a late frost.

USDA Zone Info for Spokane

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Spokane

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