One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By reviewing the USDA zone info for Sterling it's possible to estimate when you can plant bunching onions.

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.

You can plant bunching onions slightly earlier in the year because they do ok in moderate cold.

The earliest that you can plant bunching onions in Sterling 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. Any later than that and your bunching onions may not have a chance to fully mature. If you are starting your bunching onions indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Sterling. You can expect an average low temperature of -20°F in the coldest months of winter.

Since the USDA zone info for Sterling is an average the actual date of last frost is different every year. Half of the time in Sterling you get a frost after April 15 so be sure to be ready to protect your bunching onions if you have one of those late frosts.

USDA Zone Info for Sterling

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°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 -15°F.

Plants to Grow in Sterling

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