Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of getting a good idea when to plant tree onions is to look at the USDA zone info for Bonne Terre.

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 do ok in moderate cold which means that you can plant them slightly earlier than other frost tender plants.

The earliest that you can plant tree onions in Bonne Terre 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. Any later than that and your tree onions may not have a chance to really do well. You can get started a little bit earlier by starting your tree onions indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Bonne Terre. It might get as low as -10°F during the coldest months of winter.

Just be sure to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Bonne Terre and it changes from year to year. Half of the time in Bonne Terre you get surprised by a frost after April 15 so be sure to be ready to protect your tree onions in the event of a late frost.

USDA Zone Info for Bonne Terre

Here is the info for USDA Zone 6a.

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

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

Plants to Grow in Bonne Terre

You may be interested in your other planting guides for Bonne Terre.