One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You can determine when it's the best time to plant calendula in Altoona by reviewing the USDA zone info.

Planting Calendar for Calendula

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

Calendula do well in moderate cold which tells us that you can plant them earlier than plants that are more sensitive to the cold.

The earliest that you can plant calendula 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 calendula and expect a good harvest is probably August. If you wait any later than that and your calendula may not have a chance to really do well. You can get started a couple of weeks earlier by starting your calendula indoors.

Last Frost Date

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

It's important to remember that USDA zone info for Altoona is an average and the actual date of last frost changes from year to year. Since half of the time in Altoona last frost occurs after May 15 be ready to cover your calendula 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.