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.

By using the USDA zone info for Chatham you should be able to determine when it's the best time to plant onions.

Planting Calendar for Onions

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

Since onions are very cold tolerant you can plant them much earlier in the year than other frost tender plants.

The earliest that you can plant onions in Chatham 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. Any later than that and your onions may not have a chance to fully mature. Starting your onions indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Chatham. It might get as low as -10°F during the coldest months of winter.

Since the USDA zone info for Chatham 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 Chatham you get a frost after April 15 so be sure to be ready to protect your onions if you have one of those late frosts.

USDA Zone Info for Chatham

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Chatham

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