Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can figure out when it's a good idea to plant marigold in Portland by reviewing the USDA zone info.

Planting Calendar for Marigold

Frost tolerance for marigold:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Since marigold do not do well in cold weather you really should wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant marigold 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 marigold and expect a good harvest is probably August. If you wait any later than that and your marigold may not have a chance to grow to maturity. If you are starting your marigold 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 April 15 in Portland. It might get as low as -15°F during the coldest months of winter.

Just be sure to remember 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 will vary from year to year. Half of the time in Portland it frosts late in the year after April 15 so make sure that you are ready to cover your marigold 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.