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.

The USDA zone info for Washington can be looked at to determine when it's possible to plant oxalis.

Planting Calendar for Oxalis

Frost tolerance for oxalis:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Oxalis do not do well in cold weather which means that you really should wait until it warms up after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant oxalis in Washington is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant oxalis and expect a good harvest is probably August. If you wait any later than that and your oxalis may not have a chance to grow to maturity. Starting your oxalis indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Washington. You should expect an average low temperature of -10°F in the coldest months of winter.

Just be sure to remember that USDA zone info for Washington may not be accurate from year to year and the actual date of last frost will vary from year to year. Half of the time in Washington it frosts late in the year after April 15 so always be ready to cover your oxalis in the event of a surprise late frost.

USDA Zone Info for Washington

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Washington

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