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.

By checking out the USDA zone info for Portland it's a good idea to estimate when it's a good idea to plant melampodium.

Planting Calendar for Melampodium

Frost tolerance for melampodium:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Since melampodium require warm weather you really should wait until after the last frost has passed before you can plant them.

The earliest that you can plant melampodium 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 melampodium and expect a good harvest is probably August. If you wait any later than that and your melampodium may not have a chance to grow to maturity. If you are starting your melampodium indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Portland. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Portland is not always accurate the actual date of last frost can change quite a bit from year to year. Since half of the time in Portland last frost occurs after April 15 be ready to cover your melampodium 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.