One of the best tools that you have as gardeners to help us determine 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 will be able to estimate when it's a good idea to plant dahlias by looking at the USDA zone info for San Marino.

Planting Calendar for Dahlias

Frost tolerance for dahlias:	Not tolerant of frost.
When to plant:	After the last frost.

Since dahlias are not cold tolerant you really should wait until after the last frost before you can plant them.

The earliest that you can plant dahlias in San Marino 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 dahlias and expect a good harvest is probably September. Any later than that and your dahlias may not have a chance to really do well. Starting your dahlias indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In San Marino the average date of last frost happens on January 31. It might get as low as 30°F during the coldest months of winter.

Always keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for San Marino and it will vary from year to year. Since half of the time in San Marino last frost occurs after January 31 be ready to protect your dahlias in the event of one of those late frosts.

USDA Zone Info for San Marino

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 San Marino

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