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.

The USDA zone info for Eugene can be reviewed to determine when you can plant tree onions.

Planting Calendar for Tree onions

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

Tree onions do ok in a tiny bit of cold which tells us that you can plant them slightly earlier in the year than more sensitive plants.

The earliest that you can plant tree onions in Eugene 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 tree onions and expect a good harvest is probably August. You probably don't want to wait any later than that or else your tree onions may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your tree onions indoors.

Last Frost Date

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

Just be sure to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Eugene and it changes from year to year. Half of the time in Eugene last frost occurs after March 15 so be sure to be ready to protect your tree onions in the event of one of those late frosts.

USDA Zone Info for Eugene

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 Eugene

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