One of the best tools that you have as gardeners to help us determine 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 using the USDA zone info for Walnut you should be able to determine when to 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.

Petunias do ok in a tiny bit of cold which means that you can plant them a bit earlier in the year than other frost tender plants.

The earliest that you can plant petunias in Walnut 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. You probably don't want to wait any later than that or else your petunias may not have a chance to fully mature. If you are starting your petunias indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

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

Keep in mind that USDA zone info for Walnut is just an average and the actual date of last frost will vary from year to year. Half of the time in Walnut you get surprised by a frost after January 31 so make sure that you are ready to cover your petunias if you have a surprise late frost.

USDA Zone Info for Walnut

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 Walnut

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