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.

One way of determining when to plant cosmos is to look at the USDA zone info for Altoona.

Planting Calendar for Cosmos

Frost tolerance for cosmos:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since cosmos are barely cold tolerant you can plant them a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant cosmos 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 cosmos and expect a good harvest is probably August. Any later than that and your cosmos may not have a chance to fully mature. You can get started a little bit earlier by starting your cosmos indoors.

Last Frost Date

In Altoona the average date of last frost happens on April 15. It might get as low as -20°F during the coldest months of winter.

Since the USDA zone info for Altoona may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in Altoona there is a last frost after April 15 so make sure that you are prepared to cover your cosmos in the event of one of those late frosts.

USDA Zone Info for Altoona

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Altoona

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