One of the first steps you take when you are getting a good idea your gardening schedule is find your 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.

A way of determining when it's the best time to plant yarrow is to look at the USDA zone info for Altoona.

Planting Calendar for Yarrow

Frost tolerance for yarrow:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Yarrow tend to make it in cold weather which means that you can plant them much earlier in the year than other plants that might not handle the cold.

The earliest that you can plant yarrow 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 yarrow and expect a good harvest is probably August. If you wait any later than that and your yarrow may not have a chance to fully mature. Starting your yarrow indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is May 15 in Altoona. It might get as low as -25°F during the coldest months of winter.

Since the USDA zone info for Altoona is an average the actual date of last frost will vary from year to year. Half of the time in Altoona last frost occurs after May 15 so just be sure to be ready to protect your yarrow 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.