The USDA Zone info is a great tool for gardeners to help us figure out 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.

It's a good idea to determine when to plant four-o-clock flower by referring to the USDA zone info for Altoona.

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.

Four-o-clock flower do not do well in cold weather which means that it's necessary to wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant four-o-clock flower in Altoona 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 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 grow to maturity. You can get started a little bit earlier by starting your four-o-clock flower indoors.

Last Frost Date

On average the last frost has passed is on May 15 in Altoona. In the coldest months of winter you should expect an average low temperature of -25°F.

Remember that USDA zone info for Altoona is an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Altoona there is a last frost after May 15 so always be ready to protect your four-o-clock flower in the event of one of those late frosts.

USDA Zone Info for Altoona

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 Altoona

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