One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In National City you can determine when to plant polygonums by checking out the USDA zone info.

Planting Calendar for Polygonums

Frost tolerance for polygonums:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Since polygonums are not cold tolerant you have to wait until after the last frost has passed before you can plant them.

The earliest that you can plant polygonums in National City 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. If you wait any later than that and your polygonums may not have a chance to really do well. You can get started a little bit earlier by starting your polygonums indoors.

Last Frost Date

In National City the average date of last frost happens on January 31. You should expect an average low temperature of 35°F in the coldest months of winter.

Remember that USDA zone info for National City is just an average and the actual date of last frost can change quite a bit from year to year. Half of the time in National City there is a last frost after January 31 so make sure that you are prepared to cover your polygonums if you have a late frost.

USDA Zone Info for National City

Here is the info for USDA Zone 10b.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	35°F
Highest Expected Low	40°F

This means that on a really cold year, the coldest it will get is 35°F. On most years you should be prepared to experience lows near 40°F.

Plants to Grow in National City

You may be interested in your other planting guides for National City.