One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of figuring out when it's a good idea to plant onions is to use the USDA zone info for Crookston.

Planting Calendar for Onions

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

Onions are one of those plants that can tolerate quite a bit of cold weather which tells us that you can start planting them much earlier than other plants that might not handle the cold.

The earliest that you can plant onions in Crookston 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. If you are starting your onions indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Crookston the average date of last frost happens on May 15. You should expect an average low temperature of -30°F in the coldest months of winter.

Keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Crookston and it is different every year. Half of the time in Crookston it frosts late in the year after May 15 so make sure that you are prepared to protect your onions in the event of a late frost.

USDA Zone Info for Crookston

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Crookston

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