Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Rialto you can figure out when to plant yarrow by checking out the USDA zone info.

Planting Calendar for Yarrow

Frost tolerance for yarrow:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Yarrow do well in cold which tells us that you can plant them much earlier than other plants that might not handle the cold.

The earliest that you can plant yarrow in Rialto 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 yarrow and expect a good harvest is probably October. You probably don't want to wait any later than that or else your yarrow may not have a chance to really do well. Starting your yarrow indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is January 31 in Rialto. You can expect an average low temperature of 30°F in the coldest months of winter.

Just be sure to remember that USDA zone info for Rialto is not always accurate and the actual date of last frost will vary from year to year. Half of the time in Rialto it frosts late in the year after January 31 so always be ready to protect your yarrow in the event of a surprise late frost.

USDA Zone Info for Rialto

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in Rialto

You may be interested in your other planting guides for Rialto.