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.

A common way of getting a good idea when it's possible to plant lisianthus is to look at the USDA zone info for Portola Valley.

Planting Calendar for Lisianthus

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

Lisianthus are not cold tolerant which means that it's important to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant lisianthus in Portola Valley 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 lisianthus and expect a good harvest is probably September. Any later than that and your lisianthus may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your lisianthus indoors.

Last Frost Date

In Portola Valley 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.

Keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Portola Valley and it is different every year. Half of the time in Portola Valley you get surprised by a frost after January 31 so be sure to be ready to protect your lisianthus in the event of a surprise late frost.

USDA Zone Info for Portola Valley

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 Portola Valley

You may be interested in your other planting guides for Portola Valley.