One of the best tools that you have as gardeners to help us estimate 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.

In Diamond Bar you can estimate when it's a good idea to plant petunias by referring to the USDA zone info.

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.

You can plant petunias just a tiny bit earlier in the year because they do ok in moderate cold.

The earliest that you can plant petunias in Diamond Bar 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. Any later than that and your petunias may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your petunias indoors.

Last Frost Date

In Diamond Bar the average date of last frost happens on January 31. You should expect an average low temperature of 30°F in the coldest months of winter.

Always keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Diamond Bar and it changes from year to year. Half of the time in Diamond Bar you get surprised by a frost after January 31 so make sure that you are ready to cover your petunias in the event of one of those late frosts.

USDA Zone Info for Diamond Bar

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 Diamond Bar

You may be interested in your other planting guides for Diamond Bar.