Before planting it is a good idea to find your USDA Zone info to estimate 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.

A common way of getting a good idea when you can plant onions is to refer to the USDA zone info for Fairview Heights.

Planting Calendar for Onions

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

Onions do ok in pretty solid cold which means that you can plant them earlier in the year than other plants that might not handle the cold.

The earliest that you can plant onions in Fairview Heights 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 grow to maturity. If you are starting your onions indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Fairview Heights the average date of last frost happens on April 15. You can expect an average low temperature of -5°F in the coldest months of winter.

Always keep in mind that USDA zone info for Fairview Heights is just an average and the actual date of last frost will vary from year to year. Since half of the time in Fairview Heights you get a frost after April 15 be ready to cover your onions if you have one of those late frosts.

USDA Zone Info for Fairview Heights

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 Low	0°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 Fairview Heights

You may be interested in your other planting guides for Fairview Heights.