One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The earliest that you can plant alyssum in Portland can be figured out 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.

Alyssum tend to make it in cold weather which means that you can plant them a lot earlier in the year than other plants that might not handle the cold.

The earliest that you can plant alyssum in Portland 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 really do well. Starting your alyssum indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Portland. You should expect an average low temperature of 0°F in the coldest months of winter.

Keep in mind that USDA zone info for Portland is just an average and the actual date of last frost is different every year. Half of the time in Portland you get a frost after April 15 so make sure that you are prepared to protect your alyssum in the event of a late frost.

USDA Zone Info for Portland

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 Portland

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