Before planting it is a good idea to find your USDA Zone info to figure out 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 first chance to plant sunflowers in Altoona should be estimated by checking out the USDA zone info.

Planting Calendar for Sunflowers

Frost tolerance for sunflowers:	Not tolerant of frost.
When to plant:	After the last frost has passed.

It's probably not a good idea to plant sunflowers until after the last frost when the weather gets warmer because they are not cold tolerant.

The earliest that you can plant sunflowers 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 sunflowers and expect a good harvest is probably August. You probably don't want to wait any later than that or else your sunflowers may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your sunflowers indoors.

Last Frost Date

On average the last frost is on April 15 in Altoona. In the coldest months of winter you should expect an average low temperature of -10°F.

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. Since half of the time in Altoona it frosts late in the year after April 15 be ready to protect your sunflowers in the event of one of those late frosts.

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.