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.

One way of determining when it's a good idea to plant helianthemum is to look at the USDA zone info for Vallejo.

Planting Calendar for Helianthemum

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

Since helianthemum are moderately cold tolerant you can plant them a little earlier in the year than other frost tender plants.

The earliest that you can plant helianthemum in Vallejo 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. You probably don't want to wait any later than that or else your helianthemum may not have a chance to really do well. You can get started a couple of weeks earlier by starting your helianthemum indoors.

Last Frost Date

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

Remember that USDA zone info for Vallejo may not be accurate from year to year and the actual date of last frost is different every year. Half of the time in Vallejo you get surprised by a frost after February 15 so be sure to be ready to cover your helianthemum in the event of a late frost.

USDA Zone Info for Vallejo

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 Vallejo

You may be interested in your other planting guides for Vallejo.