The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A common way of estimating when it's the best time to plant datura is to check out the USDA zone info for Rialto.

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 are one of those plants that can tolerate a tiny bit of cold weather which means that you can plant them slightly earlier than other plants that might not handle the cold.

The earliest that you can plant datura in Rialto 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. You probably don't want to wait any later than that or else your datura may not have a chance to really do well. Starting your datura indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average all chance of frost has passed is on January 31 in Rialto. You can expect an average low temperature of 30°F in the coldest months of winter.

Since the USDA zone info for Rialto is not always accurate the actual date of last frost is different every year. Half of the time in Rialto you get surprised by a frost after January 31 so always be ready to protect your datura in the event of a surprise late frost.

USDA Zone Info for Rialto

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 Rialto

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