One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By using the USDA zone info for Santa Clara you will be able to estimate when it's a good idea to plant zinnia.

Planting Calendar for Zinnia

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

You can not plant zinnia until after all chance of frost has passed because they require warm weather.

The earliest that you can plant zinnia in Santa Clara 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 zinnia and expect a good harvest is probably September. If you wait any later than that and your zinnia may not have a chance to fully mature. If you are starting your zinnia 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 February 15 in Santa Clara. In the coldest months of winter you should expect an average low temperature of 25°F.

Since the USDA zone info for Santa Clara is just an average the actual date of last frost will vary from year to year. Half of the time in Santa Clara last frost occurs after February 15 so just be sure to be ready to cover your zinnia if you have a late frost.

USDA Zone Info for Santa Clara

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 Santa Clara

You may be interested in your other planting guides for Santa Clara.