One of the first steps you take when you are getting a good idea 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.

In Coronado you can estimate when it's the best time to plant tree onions by checking out 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 do ok in moderate cold which means that you can start planting them slightly earlier than other plants that might not handle the cold.

The earliest that you can plant tree onions in Coronado 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 grow to maturity. Starting your tree onions indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost has passed is on January 31 in Coronado. In the coldest months of winter you should expect an average low temperature of 35°F.

Always keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Coronado and it is different every year. Since half of the time in Coronado it frosts late in the year after January 31 be ready to cover your tree onions if you have a late frost.

USDA Zone Info for Coronado

Here is the info for USDA Zone 10b.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	35°F
Highest Expected Low	40°F

This means that on a really cold year, the coldest it will get is 35°F. On most years you should be prepared to experience lows near 40°F.

Plants to Grow in Coronado

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