Before planting it is a good idea to find your USDA Zone info to estimate 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.

A way of making a decision about when it's a good idea to plant zinnia is to look at the USDA zone info for San Marcos.

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 all chance of frost has passed because they do not do well in cold weather.

The earliest that you can plant zinnia in San Marcos 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. If you wait any later than that and your zinnia may not have a chance to really do well. You can get started a little bit earlier by starting your zinnia indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on January 31 in San Marcos. It might get as low as 30°F during the coldest months of winter.

It's important to remember that USDA zone info for San Marcos is not always accurate and the actual date of last frost will vary from year to year. Half of the time in San Marcos it frosts late in the year after January 31 so just be sure to be ready to cover your zinnia in the event of a late frost.

USDA Zone Info for San Marcos

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 San Marcos

You may be interested in your other planting guides for San Marcos.