One of the best tools that you have as gardeners to help us estimate 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 El Cajon you can estimate when it's a good idea to plant pearl onions by referring to the USDA zone info.

Planting Calendar for Pearl onions

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

Pearl onions tend to make it in some cold which means that you can plant them slightly earlier in the year than other frost tender plants.

The earliest that you can plant pearl onions in El Cajon 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 pearl onions and expect a good harvest is probably September. Any later than that and your pearl onions may not have a chance to fully mature. If you are starting your pearl onions indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on January 31 in El Cajon. In the coldest months of winter you should expect an average low temperature of 30°F.

Since the USDA zone info for El Cajon is an average the actual date of last frost can change quite a bit from year to year. Since half of the time in El Cajon it frosts late in the year after January 31 be ready to cover your pearl onions in the event of a surprise late frost.

USDA Zone Info for El Cajon

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 El Cajon

You may be interested in your other planting guides for El Cajon.