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

You will be able to figure out when to plant onions by using the USDA zone info for Mankato.

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 quite a bit of cold which means that you can plant them a lot earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant onions in Mankato 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 onions and expect a good harvest is probably August. Any later than that and your onions may not have a chance to really do well. You can get started a little bit earlier by starting your onions indoors.

Last Frost Date

On average all chance of frost has passed is on May 15 in Mankato. It might get as low as -25°F during the coldest months of winter.

Just be sure to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Mankato and it will vary from year to year. Half of the time in Mankato you get a frost after May 15 so make sure that you are prepared to protect your onions if you have one of those late frosts.

USDA Zone Info for Mankato

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Mankato

You may be interested in your other planting guides for Mankato.