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

A way of figuring out when you can plant welsh onion is to consult the USDA zone info for Tempe.

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 well in very little cold which means that you can plant them slightly earlier in the year than other plants that might not handle the cold.

The earliest that you can plant welsh onion in Tempe 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. If you are starting your welsh onion indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is February 15 in Tempe. In the coldest months of winter you should expect an average low temperature of 25°F.

Just be sure to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Tempe and it is different every year. Half of the time in Tempe you get a frost after February 15 so make sure that you are ready to protect your welsh onion in the event of a late frost.

USDA Zone Info for Tempe

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 Tempe

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