One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Blue Island you can estimate when to plant onions by reviewing the USDA zone info.

Planting Calendar for Onions

Frost tolerance for onions:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Onions can survive in cold weather which tells us that you can plant them a lot earlier in the year than other frost tender plants.

The earliest that you can plant onions in Blue Island is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant onions and expect a good harvest is probably September. Any later than that and your onions may not have a chance to really do well. If you are starting your onions indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

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

Since the USDA zone info for Blue Island is not always accurate the actual date of last frost changes from year to year. Since half of the time in Blue Island you get surprised by a frost after April 15 be ready to cover your onions 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.