The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Riverside should be reviewed to determine when it's the best time to plant hosta.

Planting Calendar for Hosta

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

Since hosta do well in moderate cold you can plant them a little bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant hosta in Riverside 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 hosta and expect a good harvest is probably October. Any later than that and your hosta may not have a chance to grow to maturity. If you are starting your hosta indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average all chance of frost has passed 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 can change quite a bit from year to year. Half of the time in Riverside it frosts late in the year after February 15 so just be sure to be ready to protect your hosta in the event of 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.