The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Washington can be reffered to in order to estimate when to plant four o' clock.

Planting Calendar for Four O' Clock

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

It's not a good idea to plant four o' clock until after the last frost has passed because they are not cold tolerant.

The earliest that you can plant four o' clock in Washington 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. You probably don't want to wait any later than that or else your four o' clock may not have a chance to grow to maturity. Starting your four o' clock indoors is a great way to get them started a little bit earlier.

Last Frost Date

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

Just be sure to remember that the actual date of last frost is an average because it is based on the USDA zone info for Washington and it can change quite a bit from year to year. Since half of the time in Washington there is a last frost after March 15 be ready to protect your four o' clock in the event of a surprise late frost.

USDA Zone Info for Washington

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°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 15°F.

Plants to Grow in Washington

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