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 Colville should be looked at to determine when you can plant trifolium.

Planting Calendar for Trifolium

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

Trifolium do ok in moderate cold which tells us that you can get them planted just a bit earlier than plants that are more sensitive to the cold.

The earliest that you can plant trifolium in Colville 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 trifolium and expect a good harvest is probably August. Any later than that and your trifolium may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your trifolium indoors.

Last Frost Date

In Colville the average date of last frost happens on April 15. It might get as low as -10°F during the coldest months of winter.

It's important to remember that USDA zone info for Colville may not be accurate from year to year and the actual date of last frost changes from year to year. Half of the time in Colville you get a frost after April 15 so make sure that you are ready to protect your trifolium in the event of one of those late frosts.

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.