One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Umatilla you can figure out when it's the best time to plant tithonia by checking out the USDA zone info.

Planting Calendar for Tithonia

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

It's not a good idea to 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 Umatilla 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. You probably don't want to wait any later than that or else your tithonia may not have a chance to grow to maturity. Starting your tithonia indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost is on April 15 in Umatilla. You can expect an average low temperature of 5°F in the coldest months of winter.

Since the USDA zone info for Umatilla may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in Umatilla last frost occurs after April 15 so always be ready to protect your tithonia if you have a late frost.

USDA Zone Info for Umatilla

Here is the info for USDA Zone 7b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	5°F
Highest Expected Low	10°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 10°F.

Plants to Grow in Umatilla

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