Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can estimate when you can plant welsh onion in Simi Valley by referring to the USDA zone info.

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 plants that might not handle the cold.

The earliest that you can plant welsh onion in Simi Valley 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. You probably don't want to wait any later than that or else your welsh onion may not have a chance to grow to maturity. If you are starting your welsh onion indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average the last frost is on February 15 in Simi Valley. It might get as low as 25°F during the coldest months of winter.

Since the USDA zone info for Simi Valley is not always accurate the actual date of last frost can change quite a bit from year to year. Half of the time in Simi Valley last frost occurs after February 15 so make sure that you are prepared to protect your welsh onion if you have a late frost.

USDA Zone Info for Simi Valley

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 Simi Valley

You may be interested in your other planting guides for Simi Valley.