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

A way of determining when it's possible to plant onions is to examine the USDA zone info for Preston.

Planting Calendar for Onions

Frost tolerance for onions:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Onions can survive in cold weather which means that you can plant them earlier in the year than other plants that might not handle the cold.

The earliest that you can plant onions in Preston 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 onions and expect a good harvest is probably September. Any later than that and your onions may not have a chance to fully mature. Starting your onions indoors is a great way to get them started a little bit earlier.

Last Frost Date

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

Since the USDA zone info for Preston may not be accurate from year to year the actual date of last frost changes from year to year. Since half of the time in Preston you get a frost after April 15 be ready to cover your onions if you have one of those late frosts.

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.