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.

In Porterville you can determine when it's a good idea to plant onions by referring to the USDA zone info.

Planting Calendar for Onions

Frost tolerance for onions:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Onions are very cold tolerant which tells us that you can get them planted much earlier than more sensitive plants.

The earliest that you can plant onions 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 onions and expect a good harvest is probably October. If you wait any later than that and your onions may not have a chance to fully mature. If you are starting your onions indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average all chance of frost has passed is on February 15 in Porterville. It might get as low as 25°F during the coldest months of winter.

Remember that USDA zone info for Porterville is just an average and the actual date of last frost will vary from year to year. Half of the time in Porterville you get surprised by a frost after February 15 so make sure that you are prepared to cover your onions in the event of a 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.