One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of determining when it's the best time to plant spinach is to consult the USDA zone info for Portland.

Planting Calendar for Spinach

Frost tolerance for spinach:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Spinach do well in moderate cold which tells us that you can start planting them earlier than other plants that might not handle the cold.

The earliest that you can plant spinach 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 spinach and expect a good harvest is probably September. If you wait any later than that and your spinach may not have a chance to fully mature. You can get started a little bit earlier by starting your spinach indoors.

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.

Just be sure to remember that USDA zone info for Portland is just an average and the actual date of last frost changes from year to year. Since half of the time in Portland it frosts late in the year after April 15 be ready to cover your spinach in the event of a 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.