When to Plant Onions in Sunnyside, WA

One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Sunnyside can be used to estimate when it's the best time to plant onions.


Planting Calendar for Onions

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

Onions do ok in pretty solid cold which tells us that you can plant them a lot earlier in the year than other frost tender plants.

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 Sunnyside 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 grow to maturity. You can get started a few weeks earlier by starting your onions indoors.

Last Frost Date

In Sunnyside the average date of last frost happens on April 15. You should expect an average low temperature of 0°F in the coldest months of winter.

Since the USDA zone info for Sunnyside is an average the actual date of last frost changes from year to year. Since half of the time in Sunnyside you get surprised by a frost after April 15 be ready to protect your onions in the event of a surprise late frost.

USDA Zone Info for Sunnyside

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low0°F
Highest Expected Low5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Sunnyside

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