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

You will be able to estimate when it's a good idea to plant spearmint by referring to the USDA zone info for Tualatin.

Planting Calendar for Spearmint

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

Spearmint tend to make it in cold weather which means that you can plant them much earlier in the year than more sensitive plants.

The earliest that you can plant spearmint in Tualatin 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 spearmint and expect a good harvest is probably September. Any later than that and your spearmint may not have a chance to fully mature. If you are starting your spearmint indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is March 15 in Tualatin. In the coldest months of winter you can expect an average low temperature of 15°F.

Keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Tualatin and it can change quite a bit from year to year. Half of the time in Tualatin you get surprised by a frost after March 15 so make sure that you are prepared to cover your spearmint in the event of one of those late frosts.

USDA Zone Info for Tualatin

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°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 20°F.

Plants to Grow in Tualatin

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