The USDA Zone info is a great tool for gardeners to help us determine your gardening 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 determining when to plant four-o-clock flower is to use 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 all chance of frost has passed.

Since four-o-clock flower do not do well in cold weather it's 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 flower in Altoona 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 grow to maturity. Starting your four-o-clock flower indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

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

Always 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 Altoona and it can change quite a bit from year to year. Half of the time in Altoona last frost occurs after April 15 so make sure that you are ready to protect your four-o-clock flower if you have a late frost.

USDA Zone Info for Altoona

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°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 -5°F.

Plants to Grow in Altoona

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