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.

By checking out the USDA zone info for Columbia you should be able to estimate when it's the best time to plant welsh onion.

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.

You can plant welsh onion a bit earlier in the year because they are barely cold tolerant.

The earliest that you can plant welsh onion in Columbia 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 welsh onion and expect a good harvest is probably August. If you wait any later than that and your welsh onion may not have a chance to fully mature. Starting your welsh onion indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Columbia the average date of last frost happens on March 15. You can expect an average low temperature of 10°F in the coldest months of winter.

Just be sure to remember that USDA zone info for Columbia is an average and the actual date of last frost changes from year to year. Half of the time in Columbia there is a last frost after March 15 so just be sure to be ready to protect your welsh onion if you have a late frost.

USDA Zone Info for Columbia

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°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 15°F.

Plants to Grow in Columbia

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