One of the first steps you take when you are determining 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.

You can figure out when it's a good idea to plant sweet williams in Rialto by looking at the USDA zone info.

Planting Calendar for Sweet Williams

Frost tolerance for sweet williams:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Since sweet williams are moderately cold tolerant you can plant them just a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant sweet williams in Rialto is January. However, you really should wait until February if you don't want to take any chances.

The last month that you can plant sweet williams and expect a good harvest is probably October. You probably don't want to wait any later than that or else your sweet williams may not have a chance to grow to maturity. Starting your sweet williams indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Rialto the average date of last frost happens on January 31. In the coldest months of winter you can expect an average low temperature of 30°F.

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 last frost occurs after January 31 so make sure that you are ready to cover your sweet williams if you have a 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.