One of the best tools that you have as gardeners to help us estimate 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 possible to plant helianthemum in Los Altos by referring to the USDA zone info.

Planting Calendar for Helianthemum

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

Helianthemum do well in moderate cold which means that you can start planting them earlier than plants that are more sensitive to the cold.

The earliest that you can plant helianthemum in Los Altos 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 helianthemum and expect a good harvest is probably October. If you wait any later than that and your helianthemum may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your helianthemum indoors.

Last Frost Date

In Los Altos the average date of last frost happens on February 15. It might get as low as 25°F during the coldest months of winter.

Since the USDA zone info for Los Altos is just an average the actual date of last frost changes from year to year. Half of the time in Los Altos it frosts late in the year after February 15 so be sure to be ready to protect your helianthemum if you have a late frost.

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.