One of the first steps you take when you are making a decision about your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Fairfax you can figure out 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.

Since onions are very cold tolerant you can plant them much earlier in the year than plants that are more sensitive to the cold.

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

Last Frost Date

The average date of last frost is February 15 in Fairfax. In the coldest months of winter you should expect an average low temperature of 25°F.

Always keep in mind that USDA zone info for Fairfax may not be accurate from year to year and the actual date of last frost changes from year to year. Half of the time in Fairfax you get surprised by a frost after February 15 so make sure that you are prepared to cover your onions if you have a late frost.

USDA Zone Info for Fairfax

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 Fairfax

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