frostdate name logo in white
frostdate name logo in white

When to Plant Welsh onion in Harrisburg, IL

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.

It's possible to figure out when to plant welsh onion by using the USDA zone info for Harrisburg.


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 are one of those plants that can tolerate a tiny bit of cold weather you can plant them slightly earlier in the year than other plants that might not handle the cold.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant welsh onion
Possibly ok, but a risky time to plant welsh onion
Probably not a good time to plant welsh onion

The earliest that you can plant welsh onion in Harrisburg 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 fully mature. Starting your welsh onion indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Harrisburg the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -5°F.

Just be sure to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Harrisburg and it changes from year to year. Since half of the time in Harrisburg you get surprised by a frost after April 15 be ready to cover your welsh onion if you have a surprise late frost.

USDA Zone Info for Harrisburg

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 Low0°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 Harrisburg

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