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.

You should be able to estimate when it's possible to plant gomphrena by checking out the USDA zone info for Washington.

Planting Calendar for Gomphrena

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

Since gomphrena are one of those plants that can tolerate a tiny bit of cold weather you can plant them just a tiny bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant gomphrena in Washington 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 gomphrena and expect a good harvest is probably August. Any later than that and your gomphrena may not have a chance to really do well. Starting your gomphrena indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Washington the average date of last frost happens on March 15. You can expect an average low temperature of 10°F in the coldest months of winter.

Keep in mind 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 changes from year to year. Half of the time in Washington there is a last frost after March 15 so make sure that you are ready to protect your gomphrena if you have a surprise late frost.

USDA Zone Info for Washington

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°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 15°F.

Plants to Grow in Washington

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