One of the first steps you take when you are getting a good idea 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.

By using the USDA zone info for Rio Vista you should be able to determine when you can plant hollyhocks.

Planting Calendar for Hollyhocks

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

Hollyhocks do well in moderate cold which means that you can get them planted earlier than more sensitive plants.

The earliest that you can plant hollyhocks in Rio Vista 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 hollyhocks and expect a good harvest is probably October. If you wait any later than that and your hollyhocks may not have a chance to really do well. Starting your hollyhocks indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is February 15 in Rio Vista. In the coldest months of winter you should expect an average low temperature of 25°F.

Since the USDA zone info for Rio Vista is not always accurate the actual date of last frost can change quite a bit from year to year. Since half of the time in Rio Vista it frosts late in the year after February 15 be ready to protect your hollyhocks in the event of a late frost.

USDA Zone Info for Rio Vista

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 Rio Vista

You may be interested in your other planting guides for Rio Vista.