Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The best time to plant tall phlox in Altoona can be estimated by checking out the USDA zone info.

Planting Calendar for Tall Phlox

Frost tolerance for tall phlox:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Tall Phlox are moderately cold tolerant which means that you can start planting them earlier than plants that are more sensitive to the cold.

The earliest that you can plant tall phlox in Altoona is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant tall phlox and expect a good harvest is probably August. Any later than that and your tall phlox may not have a chance to grow to maturity. If you are starting your tall phlox indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is May 15 in Altoona. You should expect an average low temperature of -25°F in the coldest months of winter.

Always keep in mind that USDA zone info for Altoona is an average and the actual date of last frost will vary from year to year. Half of the time in Altoona there is a last frost after May 15 so be sure to be ready to protect your tall phlox if you have a surprise late frost.

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.