One of the first steps you take when you are determining your gardening schedule is find your 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.

The USDA zone info for Zone 9a can be reffered to in order to determine when you can plant datura.

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.

You can plant datura slightly earlier in the year because they are barely cold tolerant.

The earliest that you can plant datura in Zone 9a 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. If you wait any later than that and your datura may not have a chance to really do well. Starting your datura indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is February 15 in Zone 9a. It might get as low as 20°F during the coldest months of winter.

Keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Zone 9a and it can change quite a bit from year to year. Half of the time in Zone 9a there is a last frost after February 15 so make sure that you are prepared to protect your datura if you have a surprise late frost.

USDA Zone Info for Zone 9a

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°F

This means that on a really cold year, the coldest it will get is 20°F. On most years you should be prepared to experience lows near 25°F.

Plants to Grow in Zone 9a

You may be interested in your other planting guides for Zone 9a.