When to Plant Onions in Parker, CO

Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By referring to the USDA zone info for Parker it's a good idea to determine when you can plant onions.


Planting Calendar for Onions

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

Since onions are very cold tolerant you can plant them much earlier in the year than plants that are more sensitive to the cold.

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

The earliest that you can plant onions in Parker 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. You probably don't want to wait any later than that or else your onions may not have a chance to fully mature. You can get started a little bit earlier by starting your onions indoors.

Last Frost Date

The average date of last frost is April 15 in Parker. 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 Parker is just an average and the actual date of last frost is different every year. Half of the time in Parker you get surprised by a frost after April 15 so just be sure to be ready to cover your onions in the event of a late frost.

USDA Zone Info for Parker

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 Parker

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