One of the first steps you take when you are making a decision about your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Washington you can estimate when it's possible to plant calla lily by checking out the USDA zone info.

Planting Calendar for Calla Lily

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

You really shouldn't plant calla lily until after all chance of frost has passed because they require warm weather.

The earliest that you can plant calla lily 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 calla lily and expect a good harvest is probably August. Any later than that and your calla lily may not have a chance to fully mature. If you are starting your calla lily indoors then you might be able to get away with starting them a couple of 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.

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 Washington and it can change quite a bit from year to year. Since half of the time in Washington you get a frost after April 15 be ready to cover your calla lily in the event of one of those late frosts.

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.