One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of estimating when it's a good idea to plant tree onions is to examine the USDA zone info for Huntsville.

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 are one of those plants that can tolerate a tiny bit of cold weather which tells us that you can get them planted just a bit earlier than other plants that might not handle the cold.

The earliest that you can plant tree onions in Huntsville 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. If you are starting your tree onions indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Huntsville the average date of last frost happens on April 15. You can expect an average low temperature of 5°F in the coldest months of winter.

Since the USDA zone info for Huntsville is an average the actual date of last frost is different every year. Since half of the time in Huntsville last frost occurs after April 15 be ready to cover your tree onions if you have a late frost.

USDA Zone Info for Huntsville

Here is the info for USDA Zone 7b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	5°F
Highest Expected Low	10°F

This means that on a really cold year, the coldest it will get is 5°F. On most years you should be prepared to experience lows near 10°F.

Plants to Grow in Huntsville

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