Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. 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 estimate when it's possible to plant onions by looking at the USDA zone info for New Castle.

Planting Calendar for Onions

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

Onions are one of those plants that can tolerate quite a bit of cold weather which means that you can plant them much earlier than plants that are more sensitive to the cold.

The earliest that you can plant onions in New Castle 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. You can get started a little bit earlier by starting your onions indoors.

Last Frost Date

The average date of last frost is April 15 in New Castle. In the coldest months of winter you should expect an average low temperature of 0°F.

Since the USDA zone info for New Castle is an average the actual date of last frost can change quite a bit from year to year. Half of the time in New Castle last frost occurs after April 15 so just be sure to be ready to cover your onions in the event of a late frost.

USDA Zone Info for New Castle

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in New Castle

You may be interested in your other planting guides for New Castle.