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.

A way of figuring out when you can plant four o' clock is to examine the USDA zone info for Colville.

Planting Calendar for Four O' Clock

Frost tolerance for four o' clock:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Since four o' clock require warm weather you have to wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant four o' clock in Colville is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant four o' clock and expect a good harvest is probably August. Any later than that and your four o' clock may not have a chance to fully mature. You can get started a few weeks earlier by starting your four o' clock indoors.

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 just an average the actual date of last frost will vary from year to year. Half of the time in Colville there is a last frost after April 15 so just be sure to be ready to cover your four o' clock in the event of 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.