The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first opportunity to plant four-o-clock flower in Rio Vista can be figured out by referring to the USDA zone info.

Planting Calendar for Four-o-clock flower

Frost tolerance for four-o-clock flower:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

It's probably a bad idea to plant four-o-clock flower until after all chance of frost has passed because they are not cold tolerant.

The earliest that you can plant four-o-clock flower in Rio Vista 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 four-o-clock flower and expect a good harvest is probably September. You probably don't want to wait any later than that or else your four-o-clock flower may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your four-o-clock flower indoors.

Last Frost Date

In Rio Vista the average date of last frost happens on February 15. You can expect an average low temperature of 25°F in the coldest months of winter.

Remember that the actual date of last frost is an average because it is based on the USDA zone info for Rio Vista and it can change quite a bit from year to year. Since half of the time in Rio Vista you get a frost after February 15 be ready to cover your four-o-clock flower if you have 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.