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.

You should be able to determine when to plant basil by using the USDA zone info for Zone 9a.

Planting Calendar for Basil

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

Since basil are not cold tolerant it's necessary to wait until after the last frost has passed before you can plant them.

The earliest that you can plant basil in Zone 9a 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 basil and expect a good harvest is probably September. Any later than that and your basil may not have a chance to grow to maturity. If you are starting your basil indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average the last frost has passed is on February 15 in Zone 9a. You can expect an average low temperature of 20°F in the coldest months of winter.

Keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Zone 9a and it will vary from year to year. Half of the time in Zone 9a there is a last frost after February 15 so always be ready to protect your basil in the event of a late frost.

USDA Zone Info for Zone 9a

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°F

This means that on a really cold year, the coldest it will get is 20°F. On most years you should be prepared to experience lows near 25°F.

Plants to Grow in Zone 9a

You may be interested in your other planting guides for Zone 9a.