The USDA Zone info is a great tool for gardeners to help us determine your gardening 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 Oregon should be used to figure out when it's a good idea to plant tithonia.

Planting Calendar for Tithonia

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

You really shouldn't plant tithonia until after the last frost when the weather gets warmer because they are not cold tolerant.

The earliest that you can plant tithonia in Oregon 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 tithonia and expect a good harvest is probably August. If you wait any later than that and your tithonia may not have a chance to grow to maturity. If you are starting your tithonia 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 Oregon. In the coldest months of winter you should expect an average low temperature of -5°F.

It's important to remember that USDA zone info for Oregon may not be accurate from year to year and the actual date of last frost changes from year to year. Half of the time in Oregon you get surprised by a frost after April 15 so just be sure to be ready to protect your tithonia if you have one of those late frosts.

USDA Zone Info for Oregon

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Oregon

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