One of the best tools that you have as gardeners to help us estimate your gardening schedule is the 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 figure out when to plant bunching onions by using the USDA zone info for Yorkville.

Planting Calendar for Bunching Onions

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

Since bunching onions are barely cold tolerant you can plant them slightly earlier in the year than other frost tender plants.

The earliest that you can plant bunching onions in Yorkville 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 bunching onions and expect a good harvest is probably August. If you wait any later than that and your bunching onions may not have a chance to grow to maturity. You can get started a little bit earlier by starting your bunching onions indoors.

Last Frost Date

On average the last frost is on April 15 in Yorkville. You should expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Yorkville may not be accurate from year to year the actual date of last frost is different every year. Half of the time in Yorkville last frost occurs after April 15 so make sure that you are prepared to cover your bunching onions if you have a surprise late frost.

USDA Zone Info for Yorkville

Here is the info for USDA Zone 5b.

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

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Yorkville

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