One of the best tools that you have as gardeners to help us figure out your gardening schedule is the 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.

The USDA zone info for Placentia can be reviewed to estimate when you can plant welsh onion.

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 means that you can start planting them slightly earlier than more sensitive plants.

The earliest that you can plant welsh onion in Placentia 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 fully mature. You can get started a few weeks earlier by starting your welsh onion indoors.

Last Frost Date

On average the last frost is on January 31 in Placentia. It might get as low as 30°F during the coldest months of winter.

Remember that USDA zone info for Placentia is just an average and the actual date of last frost is different every year. Half of the time in Placentia it frosts late in the year after January 31 so be sure to be ready to protect your welsh onion if you have a surprise late frost.

USDA Zone Info for Placentia

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 Placentia

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