One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first opportunity to plant datura in Petaluma should be estimated by looking at the USDA zone info.

Planting Calendar for Datura

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

Since datura are barely cold tolerant 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 datura in Petaluma 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 datura and expect a good harvest is probably September. Any later than that and your datura may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your datura 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.

Always keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Petaluma and it is different every year. Half of the time in Petaluma last frost occurs after February 15 so be sure to be ready to cover your datura 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.