One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of figuring out when you can plant tree onions is to use the USDA zone info for Duvall.

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.

You can plant tree onions just a tiny bit earlier in the year because they are barely cold tolerant.

The earliest that you can plant tree onions in Duvall 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 fully mature. You can get started a couple of weeks earlier by starting your tree onions indoors.

Last Frost Date

The average date of last frost is March 15 in Duvall. It might get as low as 15°F during the coldest months of winter.

Since the USDA zone info for Duvall is not always accurate the actual date of last frost is different every year. Since half of the time in Duvall you get surprised by a frost after March 15 be ready to cover your tree onions in the event of a late frost.

USDA Zone Info for Duvall

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 Duvall

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