The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. 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 Beaverton can be read to figure out when you can 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 well in a bit of cold which tells us that you can plant them much earlier in the year than more sensitive plants.

The earliest that you can plant onions in Beaverton 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 little bit earlier by starting your onions indoors.

Last Frost Date

The average date of last frost is March 15 in Beaverton. In the coldest months of winter you can expect an average low temperature of 15°F.

Since the USDA zone info for Beaverton may not be accurate from year to year the actual date of last frost is different every year. Half of the time in Beaverton there is a last frost after March 15 so make sure that you are prepared to cover your onions if you have a surprise late frost.

USDA Zone Info for Beaverton

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 Beaverton

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