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.

By looking at the USDA zone info for San Jose it's a good idea to determine when you can plant petunias.

Planting Calendar for Petunias

Frost tolerance for petunias:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since petunias do ok in moderate cold you can plant them just a tiny bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant petunias in San Jose 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 petunias and expect a good harvest is probably September. If you wait any later than that and your petunias may not have a chance to really do well. You can get started a couple of weeks earlier by starting your petunias indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on February 15 in San Jose. You can expect an average low temperature of 25°F in the coldest months of winter.

Remember that USDA zone info for San Jose is just an average and the actual date of last frost will vary from year to year. Since half of the time in San Jose last frost occurs after February 15 be ready to protect your petunias in the event of a late frost.

USDA Zone Info for San Jose

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 San Jose

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