One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

It's a good idea to estimate when it's a good idea to plant four o' clock by looking at the USDA zone info for Vail.

Planting Calendar for Four O' Clock

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

Since four o' clock do not do well in cold weather it is important to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant four o' clock in Vail is May. However, you really should wait until June 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 couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Vail. In the coldest months of winter you can expect an average low temperature of -25°F.

Keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Vail and it changes from year to year. Since half of the time in Vail it frosts late in the year after May 15 be ready to protect your four o' clock in the event of a late frost.

USDA Zone Info for Vail

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Vail

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