One of the best tools that you have as gardeners to help us figure out 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 Napa you can determine when you can plant tithonia by referring to the USDA zone info.

Planting Calendar for Tithonia

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

It's probably not a good idea to plant tithonia until after the last frost when the weather gets warmer because they do not do well in cold weather.

The earliest that you can plant tithonia in Napa 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. 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 Napa. In the coldest months of winter you can expect an average low temperature of 25°F.

Since the USDA zone info for Napa is an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Napa you get a frost after February 15 be ready to cover your tithonia in the event of a surprise late frost.

USDA Zone Info for Napa

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in Napa

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