The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By reviewing the USDA zone info for Sullivan it's a good idea to figure out when it's possible to plant tree onions.

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 well in some cold which tells us that you can plant them a bit earlier in the year than other frost tender plants.

The earliest that you can plant tree onions in Sullivan 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 fully mature. You can get started a little bit earlier by starting your tree onions indoors.

Last Frost Date

The average date of last frost is April 15 in Sullivan. It might get as low as 5°F during the coldest months of winter.

Keep in mind that USDA zone info for Sullivan is just an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Sullivan it frosts late in the year after April 15 so make sure that you are prepared to cover your tree onions if you have one of those late frosts.

USDA Zone Info for Sullivan

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 Sullivan

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