One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You can estimate when to plant tree onions in Fairfax by using the USDA zone info.

Planting Calendar for Tree onions

Frost tolerance for tree onions:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Tree onions tend to make it in very little cold which means that you can plant them a bit earlier in the year than more sensitive plants.

The earliest that you can plant tree onions in Fairfax 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 tree onions and expect a good harvest is probably September. Any later than that and your tree onions may not have a chance to really do well. Starting your tree onions indoors is a great way to get them started a few weeks earlier.

Last Frost Date

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

Just be sure to remember 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 a frost after February 15 so make sure that you are prepared to protect your tree onions in the event of 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.