One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can determine when to plant welsh onion in Roma by reviewing 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 are barely cold tolerant 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 welsh onion in Roma 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. 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

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

Since the USDA zone info for Roma is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in Roma it frosts late in the year after February 15 so always be ready to cover your welsh onion in the event of a late frost.

USDA Zone Info for Roma

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 Roma

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