Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. 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 it's the best time to plant onions by using the USDA zone info for Ellensburg.

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 means that you can start planting them much earlier than other frost tender plants.

The earliest that you can plant onions in Ellensburg 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. If you wait 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

The average date of last frost is April 15 in Ellensburg. It might get as low as -5°F during the coldest months of winter.

It's important to remember that USDA zone info for Ellensburg is just an average and the actual date of last frost is different every year. Since half of the time in Ellensburg last frost occurs after April 15 be ready to protect your onions if you have one of those late frosts.

USDA Zone Info for Ellensburg

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

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

Plants to Grow in Ellensburg

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