One of the first steps you take when you are determining your gardening schedule is find your 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.

It's possible to figure out when it's a good idea to plant alternaria by reviewing the USDA zone info for Riverside.

Planting Calendar for Alternaria

Frost tolerance for alternaria:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Since alternaria require warm weather you have to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant alternaria in Riverside is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant alternaria and expect a good harvest is probably September. You probably don't want to wait any later than that or else your alternaria may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your alternaria indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on February 15 in Riverside. It might get as low as 25°F during the coldest months of winter.

Since the USDA zone info for Riverside is an average the actual date of last frost will vary from year to year. Half of the time in Riverside you get a frost after February 15 so make sure that you are ready to cover your alternaria if you have one of those late frosts.

USDA Zone Info for Riverside

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in Riverside

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