The USDA Zone info is a great tool for gardeners to help us estimate 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 dahlia in Rio Vista can be figured out by reviewing the USDA zone info.

Planting Calendar for Dahlia

Frost tolerance for dahlia:	Not tolerant of frost.
When to plant:	After the last frost.

It's probably a bad idea to plant dahlia until after the last frost because they are not cold tolerant.

The earliest that you can plant dahlia 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 dahlia and expect a good harvest is probably September. Any later than that and your dahlia may not have a chance to fully mature. Starting your dahlia indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

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

Remember that USDA zone info for Rio Vista may not be accurate from year to year and the actual date of last frost will vary from year to year. Since half of the time in Rio Vista you get a frost after February 15 be ready to cover your dahlia 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.