The USDA Zone info is a great tool for gardeners to help us determine 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.

You should be able to estimate when you can plant helianthemum by looking at the USDA zone info for Porterville.

Planting Calendar for Helianthemum

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

Helianthemum tend to make it in a little bit of cold which tells us that you can plant them a little earlier in the year than other frost tender plants.

The earliest that you can plant helianthemum in Porterville 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 grow to maturity. Starting your helianthemum indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Porterville the average date of last frost happens on February 15. In the coldest months of winter you should expect an average low temperature of 25°F.

Just be sure to remember that USDA zone info for Porterville is just an average and the actual date of last frost is different every year. Since half of the time in Porterville it frosts late in the year after February 15 be ready to cover your helianthemum if you have a surprise late frost.

USDA Zone Info for Porterville

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 Porterville

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