Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Portland you can figure out when it's a good idea to plant stevia by looking at the USDA zone info.

Planting Calendar for Stevia

Frost tolerance for stevia:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Stevia are not cold tolerant which means that you must wait until it warms up after the last frost before you can plant them.

The earliest that you can plant stevia in Portland is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant stevia and expect a good harvest is probably August. Any later than that and your stevia may not have a chance to fully mature. Starting your stevia indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is March 15 in Portland. It might get as low as 15°F during the coldest months of winter.

Since the USDA zone info for Portland is just an average the actual date of last frost will vary from year to year. Half of the time in Portland you get a frost after March 15 so always be ready to protect your stevia in the event of a late frost.

USDA Zone Info for Portland

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 Portland

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