One of the best tools that you have as gardeners to help us estimate your gardening schedule is the 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.

By using the USDA zone info for Rialto you will be able to figure out when to plant oregano.

Planting Calendar for Oregano

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

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

The earliest that you can plant oregano 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 oregano and expect a good harvest is probably October. If you wait any later than that and your oregano may not have a chance to grow to maturity. You can get started a little bit earlier by starting your oregano indoors.

Last Frost Date

On average the last frost has passed is on January 31 in Rialto. In the coldest months of winter you should expect an average low temperature of 30°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 Rialto and it is different every year. Half of the time in Rialto you get a frost after January 31 so make sure that you are prepared to protect your oregano in the event of one of those late frosts.

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.