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.

You can estimate when it's a good idea to plant hardy asters in Diamond Bar by looking at the USDA zone info.

Planting Calendar for Hardy Asters

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

Since hardy asters are barely cold tolerant you can plant them just a tiny bit earlier in the year than other frost tender plants.

The earliest that you can plant hardy asters in Diamond Bar 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 hardy asters and expect a good harvest is probably September. Any later than that and your hardy asters may not have a chance to fully mature. If you are starting your hardy asters indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average the last frost has passed is on January 31 in Diamond Bar. It might get as low as 30°F during the coldest months of winter.

Since the USDA zone info for Diamond Bar is not always accurate the actual date of last frost is different every year. Half of the time in Diamond Bar you get a frost after January 31 so always be ready to cover your hardy asters if you have a late frost.

USDA Zone Info for Diamond Bar

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 Diamond Bar

You may be interested in your other planting guides for Diamond Bar.