One of the best tools that you have as gardeners to help us determine 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.

You can determine when it's a good idea to plant achimenes in Rialto by looking at the USDA zone info.

Planting Calendar for Achimenes

Frost tolerance for achimenes:	Not tolerant of frost.
When to plant:	After the last frost has passed.

You can not plant achimenes until after the last frost when the weather gets warmer because they require warm weather.

The earliest that you can plant achimenes 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 achimenes and expect a good harvest is probably September. Any later than that and your achimenes may not have a chance to grow to maturity. Starting your achimenes 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. You should expect an average low temperature of 30°F in the coldest months of winter.

Keep in mind that USDA zone info for Rialto may not be accurate from year to year and the actual date of last frost is different every year. Half of the time in Rialto last frost occurs after January 31 so always be ready to cover your achimenes if you have 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.