One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first opportunity to plant corn in Portland should be determined by reviewing the USDA zone info.

Planting Calendar for Corn

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

Corn require warm weather 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 corn 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 corn and expect a good harvest is probably August. Any later than that and your corn may not have a chance to really do well. If you are starting your corn indoors then you might be able to get away with starting them 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 can expect an average low temperature of 15°F.

Keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Portland and it can change quite a bit from year to year. Half of the time in Portland there is a last frost after March 15 so just be sure to be ready to cover your corn in the event of 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.