The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You should be able to figure out when to plant welsh onion by referring to the USDA zone info for West Covina.

Planting Calendar for Welsh onion

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

Welsh onion do ok in moderate cold which tells us that you can plant them slightly earlier than other frost tender plants.

The earliest that you can plant welsh onion in West Covina 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 welsh onion and expect a good harvest is probably September. If you wait any later than that and your welsh onion may not have a chance to really do well. You can get started a few weeks earlier by starting your welsh onion indoors.

Last Frost Date

In West Covina 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.

Keep in mind that USDA zone info for West Covina is not always accurate and the actual date of last frost can change quite a bit from year to year. Half of the time in West Covina you get surprised by a frost after January 31 so be sure to be ready to cover your welsh onion if you have a surprise late frost.

USDA Zone Info for West Covina

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 West Covina

You may be interested in your other planting guides for West Covina.