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.

The USDA zone info for Portland can be used to figure out when it's a good idea to plant chervil.

Planting Calendar for Chervil

Frost tolerance for chervil:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

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

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

The last month that you can plant chervil and expect a good harvest is probably August. If you wait any later than that and your chervil may not have a chance to grow to maturity. If you are starting your chervil indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

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

Remember that USDA zone info for Portland is an average and the actual date of last frost is different every year. Since half of the time in Portland you get surprised by a frost after April 15 be ready to cover your chervil in the event of a surprise late frost.

USDA Zone Info for Portland

Here is the info for USDA Zone 5b.

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

Plants to Grow in Portland

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