One of the first steps you take when you are making a decision about 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 chance to plant datura in Portola Valley should be figured out by using 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.

You can plant datura a bit earlier in the year because they are one of those plants that can tolerate a tiny bit of cold weather.

The earliest that you can plant datura in Portola Valley 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 few weeks earlier.

Last Frost Date

The average date of last frost is January 31 in Portola Valley. In the coldest months of winter you can expect an average low temperature of 30°F.

Since the USDA zone info for Portola Valley may not be accurate from year to year the actual date of last frost is different every year. Half of the time in Portola Valley you get a frost after January 31 so always be ready to cover your datura in the event of one of those late frosts.

USDA Zone Info for Portola Valley

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 Portola Valley

You may be interested in your other planting guides for Portola Valley.