The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A way of making a decision about when you can plant onions is to refer to the USDA zone info for Henderson.

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 cold weather which tells us that you can plant them much earlier in the year than more sensitive plants.

The earliest that you can plant onions 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 onions and expect a good harvest is probably September. 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

The average date of last frost is April 15 in Henderson. It might get as low as -5°F during the coldest months of winter.

Since the USDA zone info for Henderson may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Half of the time in Henderson you get a frost after April 15 so make sure that you are prepared to protect your onions in the event of one of those late frosts.

USDA Zone Info for Henderson

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Henderson

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