One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Mountain View you can estimate when you can plant tree onions by referring to 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.

Since tree onions are barely cold tolerant you can plant them a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant tree onions in Mountain View 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. You probably don't want to wait any later than that or else your tree onions may not have a chance to really do well. If you are starting your tree onions indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Mountain View the average date of last frost happens on January 31. You should expect an average low temperature of 30°F in the coldest months of winter.

It's important to remember that USDA zone info for Mountain View is just an average and the actual date of last frost will vary from year to year. Half of the time in Mountain View you get surprised by a frost after January 31 so always be ready to protect your tree onions if you have a surprise late frost.

USDA Zone Info for Mountain View

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in Mountain View

You may be interested in your other planting guides for Mountain View.