One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In National City you can determine when it's the best time to plant trifolium by checking out the USDA zone info.

Planting Calendar for Trifolium

Frost tolerance for trifolium:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Trifolium do well in very little cold which tells us that you can plant them just a tiny bit earlier in the year than more sensitive plants.

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

Since the USDA zone info for National City is just an average the actual date of last frost is different every year. Half of the time in National City it frosts late in the year after January 31 so always be ready to protect your trifolium 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.