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

A common way of making a decision about when it's a good idea to plant tree onions is to look at the USDA zone info for Inverness.

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 means that you can plant them a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant tree onions in Inverness is February. However, you really should wait until March 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 September. Any later than that and your tree onions may not have a chance to grow to maturity. Starting your tree onions indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is February 15 in Inverness. It might get as low as 20°F during the coldest months of winter.

Since the USDA zone info for Inverness is an average the actual date of last frost changes from year to year. Since half of the time in Inverness last frost occurs after February 15 be ready to cover your tree onions in the event of one of those late frosts.

USDA Zone Info for Inverness

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°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 25°F.

Plants to Grow in Inverness

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