One of the first steps you take when you are getting a good idea 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.

You should be able to estimate when to plant onions by using the USDA zone info for Rosemount.

Planting Calendar for Onions

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

Onions do well in pretty solid cold which means that you can plant them a lot earlier in the year than more sensitive plants.

The earliest that you can plant onions in Rosemount 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. If you wait any later than that and your onions may not have a chance to fully mature. You can get started a few weeks earlier by starting your onions indoors.

Last Frost Date

On average the last frost has passed is on May 15 in Rosemount. In the coldest months of winter you can expect an average low temperature of -25°F.

It's important to remember that USDA zone info for Rosemount is just an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Rosemount it frosts late in the year after May 15 so make sure that you are ready to protect your onions if you have a late frost.

USDA Zone Info for Rosemount

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 Rosemount

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