One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You should be able to estimate when it's the best time to plant tithonia by checking out the USDA zone info for Grass Valley.

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 tells us that you have 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 Grass Valley is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant tithonia and expect a good harvest is probably September. If you wait any later than that and your tithonia may not have a chance to fully mature. You can get started a few weeks earlier by starting your tithonia indoors.

Last Frost Date

The average date of last frost is February 15 in Grass Valley. It might get as low as 20°F during the coldest months of winter.

Keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Grass Valley and it changes from year to year. Half of the time in Grass Valley it frosts late in the year after February 15 so make sure that you are prepared to protect your tithonia in the event of a surprise late frost.

USDA Zone Info for Grass Valley

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°F

This means that on a really cold year, the coldest it will get is 20°F. On most years you should be prepared to experience lows near 25°F.

Plants to Grow in Grass Valley

You may be interested in your other planting guides for Grass Valley.