When to Plant Bunching Onions in Carbondale, CO

One of the first steps you take when you are determining 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.

You should be able to determine when to plant bunching onions by using the USDA zone info for Carbondale.


Planting Calendar for Bunching Onions

Frost tolerance for bunching onions: Tolerant of a very small amount of frost.
When to plant: Up to 3 weeks before last frost.

You can plant bunching onions slightly earlier in the year because they are barely cold tolerant.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant bunching onions
Possibly ok, but a risky time to plant bunching onions
Probably not a good time to plant bunching onions

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

Last Frost Date

In Carbondale the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -15°F.

It's important to remember that USDA zone info for Carbondale may not be accurate from year to year and the actual date of last frost is different every year. Since half of the time in Carbondale there is a last frost after April 15 be ready to cover your bunching onions in the event of a surprise late frost.

USDA Zone Info for Carbondale

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 Carbondale

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