Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Riverbank you can determine when to plant tree onions 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 are barely cold tolerant which tells us that you can plant them slightly earlier than more sensitive plants.

The earliest that you can plant tree onions in Riverbank 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. If you wait any later than that and your tree onions may not have a chance to really do well. You can get started a few weeks earlier by starting your tree onions indoors.

Last Frost Date

On average the last frost is on February 15 in Riverbank. In the coldest months of winter you can expect an average low temperature of 25°F.

Keep in mind that USDA zone info for Riverbank 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 Riverbank it frosts late in the year after February 15 so make sure that you are ready to cover your tree onions in the event of a surprise late frost.

USDA Zone Info for Riverbank

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 Riverbank

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