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.

The best time to plant onions in Henderson should be figured out by using the USDA zone info.

Planting Calendar for Onions

Frost tolerance for onions:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Onions do ok in quite a bit of cold which tells us that you can plant them earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant onions in Henderson is January. However, you really should wait until February if you don't want to take any chances.

The last month that you can plant onions and expect a good harvest is probably October. If you wait any later than that and your onions may not have a chance to fully mature. If you are starting your onions indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average the last frost has passed is on February 15 in Henderson. In the coldest months of winter you should expect an average low temperature of 20°F.

Just be sure to remember that USDA zone info for Henderson 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 Henderson last frost occurs after February 15 be ready to protect your onions in the event of a late frost.

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.