One of the best tools that you have as gardeners to help us estimate 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.

In Tualatin you can determine when it's the best time to plant bunching onions by referring to the USDA zone info.

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.

Bunching Onions do ok in some cold which tells us that you can plant them slightly earlier in the year than other plants that might not handle the cold.

The earliest that you can plant bunching onions in Tualatin 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. If you are starting your bunching onions indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

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

Always keep in mind that USDA zone info for Tualatin is not always accurate and the actual date of last frost changes from year to year. Since half of the time in Tualatin last frost occurs after March 15 be ready to cover your bunching onions in the event of a surprise late frost.

USDA Zone Info for Tualatin

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°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 20°F.

Plants to Grow in Tualatin

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