Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You should be able to determine when it's a good idea to plant zinnia by referring to the USDA zone info for Alameda.

Planting Calendar for Zinnia

Frost tolerance for zinnia:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

You should not plant zinnia 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 zinnia in Alameda is February. However, you really should wait until March 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. You probably don't want to wait any later than that or else 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 little bit earlier.

Last Frost Date

The average date of last frost is January 31 in Alameda. You should expect an average low temperature of 30°F in the coldest months of winter.

Just be sure to remember that USDA zone info for Alameda is not always accurate and the actual date of last frost changes from year to year. Half of the time in Alameda it frosts late in the year after January 31 so just be sure to be ready to protect your zinnia in the event of a surprise late frost.

USDA Zone Info for Alameda

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in Alameda

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