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

The USDA zone info for Hillsboro should be read to estimate when you can plant spearmint.

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 quite a bit of cold which means that you can plant them a lot earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant spearmint in Hillsboro 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. If you wait 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 little bit earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Hillsboro. In the coldest months of winter you can expect an average low temperature of -10°F.

Keep in mind that USDA zone info for Hillsboro is just an average and the actual date of last frost is different every year. Since half of the time in Hillsboro there is a last frost after April 15 be ready to cover your spearmint in the event of one of those late frosts.

USDA Zone Info for Hillsboro

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°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 -5°F.

Plants to Grow in Hillsboro

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