Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A common way of estimating when it's the best time to plant four-o-clock flower is to consult the USDA zone info for Blackfoot.

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 when the weather gets warmer.

Since four-o-clock flower do not do well in cold weather it's necessary to wait until after the last frost before you can plant them.

The earliest that you can plant four-o-clock flower in Blackfoot 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. If you are starting your four-o-clock flower indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Blackfoot. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Blackfoot is not always accurate the actual date of last frost will vary from year to year. Half of the time in Blackfoot you get surprised by a frost after April 15 so make sure that you are ready to cover your four-o-clock flower if you have a late frost.

USDA Zone Info for Blackfoot

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Blackfoot

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