The USDA Zone info is a great tool for gardeners to help us determine 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 Pullman can be used to figure out when it's possible to plant pyrethrum.

Planting Calendar for Pyrethrum

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

Pyrethrum can survive in mild cold which tells us that you can plant them just a bit earlier in the year than other frost tender plants.

The earliest that you can plant pyrethrum in Pullman 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. If you wait any later than that and your pyrethrum may not have a chance to fully mature. If you are starting your pyrethrum 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 Pullman. In the coldest months of winter you should expect an average low temperature of -5°F.

It's important to remember that the actual date of last frost is an average because it is based on the USDA zone info for Pullman and it will vary from year to year. Since half of the time in Pullman it frosts late in the year after April 15 be ready to protect your pyrethrum in the event of a late frost.

USDA Zone Info for Pullman

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Pullman

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