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

By checking out the USDA zone info for North Liberty you should be able to determine when it's a good idea to plant onions.

Planting Calendar for Onions

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

Since onions do well in cold you can plant them much earlier in the year than other plants that might not handle the cold.

The earliest that you can plant onions in North Liberty 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. Starting your onions indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in North Liberty. You can expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for North Liberty is an average the actual date of last frost is different every year. Half of the time in North Liberty you get a frost after April 15 so always be ready to protect your onions if you have a late frost.

USDA Zone Info for North Liberty

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 North Liberty

You may be interested in your other planting guides for North Liberty.