The USDA Zone info is a great tool for gardeners to help us figure out 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.

By using the USDA zone info for Tualatin it's a good idea to estimate 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.

Tithonia are not cold tolerant which means that it is important to wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant tithonia in Tualatin 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. Any later than that and your tithonia may not have a chance to grow to maturity. Starting your tithonia indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is March 15 in Tualatin. 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 is just an average because it is based on the USDA zone info for Tualatin and it changes from year to year. Since half of the time in Tualatin there is a last frost after March 15 be ready to protect your tithonia if you have one of those late frosts.

USDA Zone Info for Tualatin

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 Tualatin

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