One of the first steps you take when you are figuring out 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.

In Wheat Ridge you can estimate when it's possible to plant onions by looking at the USDA zone info.

Planting Calendar for Onions

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

You can plant onions a lot earlier in the year because they are very cold tolerant.

The earliest that you can plant onions in Wheat Ridge 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 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

On average the last frost is on April 15 in Wheat Ridge. It might get as low as -10°F during the coldest months of winter.

It's important to remember that USDA zone info for Wheat Ridge is just an average and the actual date of last frost changes from year to year. Since half of the time in Wheat Ridge you get a frost after April 15 be ready to cover your onions in the event of one of those late frosts.

USDA Zone Info for Wheat Ridge

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Wheat Ridge

You may be interested in your other planting guides for Wheat Ridge.