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.

The earliest that you can plant welsh onion in Vernon Hills should be estimated by checking out the USDA zone info.

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.

Welsh onion tend to make it in a tiny bit of cold which means that you can plant them slightly earlier in the year than other frost tender plants.

The earliest that you can plant welsh onion in Vernon Hills 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. You can get started a little bit earlier by starting your welsh onion indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Vernon Hills. You can expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Vernon Hills is just an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Vernon Hills you get surprised by a frost after April 15 be ready to cover your welsh onion in the event of one of those late frosts.

USDA Zone Info for Vernon Hills

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 Vernon Hills

You may be interested in your other planting guides for Vernon Hills.