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.

You should be able to determine when you can plant alternaria by checking out the USDA zone info for Petaluma.

Planting Calendar for Alternaria

Frost tolerance for alternaria:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Alternaria are not cold tolerant which means that it's important to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant alternaria in Petaluma is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant alternaria and expect a good harvest is probably September. You probably don't want to wait any later than that or else your alternaria may not have a chance to really do well. You can get started a little bit earlier by starting your alternaria indoors.

Last Frost Date

The average date of last frost is February 15 in Petaluma. In the coldest months of winter you can expect an average low temperature of 25°F.

Since the USDA zone info for Petaluma is just an average the actual date of last frost is different every year. Since half of the time in Petaluma it frosts late in the year after February 15 be ready to cover your alternaria if you have one of those late frosts.

USDA Zone Info for Petaluma

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 Petaluma

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