One of the first steps you take when you are figuring out 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.

By using the USDA zone info for Signal Hill it's possible to estimate 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.

Datura tend to make it in a tiny bit of cold which tells us that you can plant them a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant datura in Signal Hill 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 fully mature. Starting your datura indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Signal Hill the average date of last frost happens on January 31. In the coldest months of winter you should expect an average low temperature of 35°F.

Keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Signal Hill and it is different every year. Since half of the time in Signal Hill there is a last frost after January 31 be ready to protect your datura in the event of a surprise late frost.

USDA Zone Info for Signal Hill

Here is the info for USDA Zone 10b.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	35°F
Highest Expected Low	40°F

This means that on a really cold year, the coldest it will get is 35°F. On most years you should be prepared to experience lows near 40°F.

Plants to Grow in Signal Hill

You may be interested in your other planting guides for Signal Hill.