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.

In Washington you can determine when it's a good idea to plant pyrethrum by reviewing the USDA zone info.

Planting Calendar for Pyrethrum

Frost tolerance for pyrethrum:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

You can plant pyrethrum a little earlier in the year because they do well in moderate cold.

The earliest that you can plant pyrethrum in Washington 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 pyrethrum and expect a good harvest is probably September. You probably don't want to wait any later than that or else your pyrethrum may not have a chance to really do well. You can get started a little bit earlier by starting your pyrethrum indoors.

Last Frost Date

On average the last frost is on April 15 in Washington. You can expect an average low temperature of -15°F in the coldest months of winter.

Just be sure to remember that USDA zone info for Washington is just an average and the actual date of last frost will vary from year to year. Since half of the time in Washington last frost occurs after April 15 be ready to protect your pyrethrum in the event of a late frost.

USDA Zone Info for Washington

Here is the info for USDA Zone 5b.

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

Plants to Grow in Washington

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