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.

You can figure out when it's the best time to plant welsh onion in Henderson 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.

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

The earliest that you can plant welsh onion in Henderson 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. Starting your welsh onion indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Henderson the average date of last frost happens on February 15. You should expect an average low temperature of 20°F in the coldest months of winter.

Since the USDA zone info for Henderson is an average the actual date of last frost can change quite a bit from year to year. Half of the time in Henderson you get surprised by a frost after February 15 so just be sure to be ready to protect your welsh onion in the event of one of those late frosts.

USDA Zone Info for Henderson

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°F

This means that on a really cold year, the coldest it will get is 20°F. On most years you should be prepared to experience lows near 25°F.

Plants to Grow in Henderson

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