One of the first steps you take when you are making a decision about 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.

You will be able to determine when it's the best time to plant tree onions by looking at the USDA zone info for Altoona.

Planting Calendar for Tree onions

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

Tree onions can survive in some cold which tells us that you can plant them slightly earlier in the year than more sensitive plants.

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

Last Frost Date

In Altoona the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -20°F.

Since the USDA zone info for Altoona is an average the actual date of last frost will vary from year to year. Since half of the time in Altoona there is a last frost after April 15 be ready to protect your tree onions if you have a late frost.

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.