One of the first steps you take when you are making a decision about your gardening schedule is find your 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.

A way of figuring out when it's possible to plant tree onions is to examine the USDA zone info for Morro Bay.

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 do ok in moderate cold which means that you can start planting them slightly earlier than more sensitive plants.

The earliest that you can plant tree onions in Morro Bay 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. If you are starting your tree onions indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is February 15 in Morro Bay. You can expect an average low temperature of 25°F in the coldest months of winter.

Since the USDA zone info for Morro Bay is an average the actual date of last frost changes from year to year. Half of the time in Morro Bay you get a frost after February 15 so make sure that you are ready to cover your tree onions in the event of a late frost.

USDA Zone Info for Morro Bay

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 Morro Bay

You may be interested in your other planting guides for Morro Bay.