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

The first chance to plant four-o-clock flower in Prosser should be estimated by referring to the USDA zone info.

Planting Calendar for Four-o-clock flower

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

Four-o-clock flower are not cold tolerant which means that it is necessary to wait until it warms up after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant four-o-clock flower in Prosser 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 flower and expect a good harvest is probably August. If you wait any later than that and your four-o-clock flower may not have a chance to fully mature. You can get started a few weeks earlier by starting your four-o-clock flower indoors.

Last Frost Date

On average the last frost has passed is on April 15 in Prosser. You should expect an average low temperature of 0°F in the coldest months of winter.

Since the USDA zone info for Prosser is just an average the actual date of last frost will vary from year to year. Half of the time in Prosser there is a last frost after April 15 so be sure to be ready to cover your four-o-clock flower in the event of a surprise late frost.

USDA Zone Info for Prosser

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Prosser

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