One of the best tools that you have as gardeners to help us determine 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.

In Colville you can figure out when it's the best time to plant pyrethrum by looking at 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.

Pyrethrum can survive in some cold which tells us that you can plant them a bit earlier in the year than more sensitive plants.

The earliest that you can plant pyrethrum in Colville 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 little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Colville. It might get as low as -10°F during the coldest months of winter.

Since the USDA zone info for Colville is not always accurate the actual date of last frost is different every year. Since half of the time in Colville it frosts late in the year after April 15 be ready to protect your pyrethrum if you have a surprise late frost.

USDA Zone Info for Colville

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 Colville

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