One of the first steps you take when you are estimating your gardening schedule is find your 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 Portland you can figure out when it's a good idea to plant fennel by referring to the USDA zone info.

Planting Calendar for Fennel

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

Fennel do well in cold which tells us that you can get them planted much earlier than more sensitive plants.

The earliest that you can plant fennel 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 fennel and expect a good harvest is probably September. Any later than that and your fennel may not have a chance to really do well. Starting your fennel 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. In the coldest months of winter you should expect an average low temperature of 15°F.

Just be sure to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Portland and it is different every year. Since half of the time in Portland last frost occurs after March 15 be ready to cover your fennel if you have a surprise 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.