Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's possible to determine when it's the best time to plant welsh onion by referring to the USDA zone info for Wilmington.

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.

Since welsh onion do ok in moderate cold you can plant them slightly earlier in the year than other plants that might not handle the cold.

The earliest that you can plant welsh onion in Wilmington 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. You probably don't want to wait any later than that or else your welsh onion may not have a chance to grow to maturity. If you are starting your welsh onion indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Wilmington the average date of last frost happens on April 15. You should expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Wilmington is not always accurate the actual date of last frost changes from year to year. Since half of the time in Wilmington you get surprised by a frost after April 15 be ready to cover your welsh onion if you have a late frost.

USDA Zone Info for Wilmington

Here is the info for USDA Zone 5b.

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

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Wilmington

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