The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Los Altos you can estimate when to plant dahlias by looking at the USDA zone info.

Planting Calendar for Dahlias

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

Dahlias are not cold tolerant which means that you have to wait until it warms up after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant dahlias in Los Altos is March. However, you really should wait until April 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. You probably don't want to wait any later than that or else your dahlias may not have a chance to fully mature. Starting your dahlias indoors is a great way to get them started a little bit earlier.

Last Frost Date

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

Since the USDA zone info for Los Altos may not be accurate from year to year the actual date of last frost changes from year to year. Half of the time in Los Altos you get a frost after February 15 so just be sure to be ready to protect your dahlias if you have one of those late frosts.

USDA Zone Info for Los Altos

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 Los Altos

You may be interested in your other planting guides for Los Altos.