One of the best tools that you have as gardeners to help us determine 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 determining when to plant welsh onion is to consult the USDA zone info for Sierra Vista.

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.

Since welsh onion do ok in moderate cold you can plant them a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant welsh onion in Sierra Vista is March. However, you really should wait until April 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 August. 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

The average date of last frost is March 15 in Sierra Vista. You should expect an average low temperature of 15°F in the coldest months of winter.

It's important to remember that USDA zone info for Sierra Vista is an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in Sierra Vista last frost occurs after March 15 be ready to cover your welsh onion in the event of a surprise late frost.

USDA Zone Info for Sierra Vista

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°F

This means that on a really cold year, the coldest it will get is 15°F. On most years you should be prepared to experience lows near 20°F.

Plants to Grow in Sierra Vista

You may be interested in your other planting guides for Sierra Vista.