Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A common way of determining when to plant polygonums is to use the USDA zone info for Rialto.

Planting Calendar for Polygonums

Frost tolerance for polygonums:	Not tolerant of frost.
When to plant:	After the last frost has passed.

It's probably not a good idea to plant polygonums until after the last frost has passed because they are not cold tolerant.

The earliest that you can plant polygonums in Rialto is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant polygonums and expect a good harvest is probably September. You probably don't want to wait any later than that or else your polygonums may not have a chance to grow to maturity. If you are starting your polygonums indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

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

Just be sure to remember that USDA zone info for Rialto is not always accurate and the actual date of last frost changes from year to year. Since half of the time in Rialto last frost occurs after January 31 be ready to protect your polygonums if you have one of those late frosts.

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.