One of the best tools that you have as gardeners to help us estimate 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.

By looking at the USDA zone info for San Bernardino you should be able to figure out when you can plant twinspur.

Planting Calendar for Twinspur

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

You can plant twinspur a little earlier in the year because they do well in moderate cold.

The earliest that you can plant twinspur in San Bernardino 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 twinspur and expect a good harvest is probably October. Any later than that and your twinspur may not have a chance to fully mature. Starting your twinspur indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is February 15 in San Bernardino. It might get as low as 25°F during the coldest months of winter.

Since the USDA zone info for San Bernardino may not be accurate from year to year the actual date of last frost changes from year to year. Since half of the time in San Bernardino it frosts late in the year after February 15 be ready to protect your twinspur in the event of a late frost.

USDA Zone Info for San Bernardino

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 San Bernardino

You may be interested in your other planting guides for San Bernardino.