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.

The earliest that you can plant dahlia in San Bruno should be determined by using the USDA zone info.

Planting Calendar for Dahlia

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

Dahlia are not cold tolerant which tells us that it's important to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant dahlia in San Bruno 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 dahlia and expect a good harvest is probably September. Any later than that and your dahlia may not have a chance to fully mature. You can get started a few weeks earlier by starting your dahlia indoors.

Last Frost Date

In San Bruno the average date of last frost happens on January 31. You should expect an average low temperature of 30°F in the coldest months of winter.

Since the USDA zone info for San Bruno may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Half of the time in San Bruno it frosts late in the year after January 31 so make sure that you are prepared to cover your dahlia in the event of a surprise late frost.

USDA Zone Info for San Bruno

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 Bruno

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