One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You should be able to figure out when you can plant bunching onions by looking at the USDA zone info for Columbus.

Planting Calendar for Bunching Onions

Frost tolerance for bunching onions:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since bunching onions are one of those plants that can tolerate a tiny bit of cold weather you can plant them a bit earlier in the year than more sensitive plants.

The earliest that you can plant bunching onions in Columbus 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 bunching onions and expect a good harvest is probably August. Any later than that and your bunching onions may not have a chance to really do well. You can get started a couple of weeks earlier by starting your bunching onions indoors.

Last Frost Date

The average date of last frost is April 15 in Columbus. In the coldest months of winter you should expect an average low temperature of -10°F.

Keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Columbus and it changes from year to year. Since half of the time in Columbus you get a frost after April 15 be ready to protect your bunching onions in the event of a surprise late frost.

USDA Zone Info for Columbus

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 Columbus

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