One of the best tools that you have as gardeners to help us determine 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.

One way of determining when it's possible to plant bunching onions is to refer to the USDA zone info for Preston.

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.

Bunching Onions do ok in moderate cold which tells us that you can plant them slightly earlier than other frost tender plants.

The earliest that you can plant bunching onions in Preston 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 really do well. Starting your bunching onions indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Preston the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -15°F.

Remember that USDA zone info for Preston is just an average and the actual date of last frost will vary from year to year. Half of the time in Preston it frosts late in the year after April 15 so just be sure to be ready to cover your bunching onions in the event of a surprise late frost.

USDA Zone Info for Preston

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 Preston

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