One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Rio Vista you can determine when to plant pyrethrum by using the USDA zone info.

Planting Calendar for Pyrethrum

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

Pyrethrum do well in moderate cold which means that you can start planting them earlier than other plants that might not handle the cold.

The earliest that you can plant pyrethrum 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 pyrethrum and expect a good harvest is probably October. If you wait any later than that and your pyrethrum may not have a chance to really do well. You can get started a couple of weeks earlier by starting your pyrethrum indoors.

Last Frost Date

On average the last frost has passed is on February 15 in Rio Vista. You should expect an average low temperature of 25°F in the coldest months of winter.

Remember that USDA zone info for Rio Vista is not always accurate and the actual date of last frost will vary from year to year. Since half of the time in Rio Vista last frost occurs after February 15 be ready to protect your pyrethrum 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.