When to Plant Welsh onion in Wilmette, IL

Before planting it is a good idea to find your USDA Zone info to determine your garden 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 determine when it's possible to plant welsh onion by using the USDA zone info for Wilmette.


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 just a tiny bit earlier in the year because they do ok in moderate 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 Wilmette 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. Any later than that and your welsh onion may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your welsh onion indoors.

Last Frost Date

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

Remember that the actual date of last frost is an average because it is based on the USDA zone info for Wilmette and it is different every year. Half of the time in Wilmette you get a frost after April 15 so always be ready to cover your welsh onion in the event of one of those late frosts.

USDA Zone Info for Wilmette

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 Wilmette

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