The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Blue Island should be read to determine 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.

Welsh onion tend to make it in a tiny bit of cold which tells us that you can plant them a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant welsh onion in Blue Island 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 little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Blue Island. In the coldest months of winter you should expect an average low temperature of -10°F.

Since the USDA zone info for Blue Island is just an average the actual date of last frost will vary from year to year. Since half of the time in Blue Island there is a last frost after April 15 be ready to cover your welsh onion if you have one of those late frosts.

USDA Zone Info for Blue Island

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°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 -5°F.

Plants to Grow in Blue Island

You may be interested in your other planting guides for Blue Island.