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.

In Riverside you can figure out when to plant alternaria by reviewing the USDA zone info.

Planting Calendar for Alternaria

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

It's a bad idea to plant alternaria until after the last frost when the weather gets warmer because they do not do well in cold weather.

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

The last month that you can plant alternaria and expect a good harvest is probably August. Any later than that and your alternaria may not have a chance to really do well. Starting your alternaria indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Riverside. It might get as low as -10°F during the coldest months of winter.

Keep in mind that USDA zone info for Riverside is not always accurate and the actual date of last frost is different every year. Half of the time in Riverside you get a frost after April 15 so just be sure to be ready to cover your alternaria in the event of a surprise late frost.

USDA Zone Info for Riverside

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Riverside

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