One of the first steps you take when you are determining your gardening schedule is find your 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.

The USDA zone info for Smithfield should be used to figure out when it's possible to plant onions.

Planting Calendar for Onions

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

Onions do ok in quite a bit of cold which means that you can plant them a lot earlier in the year than more sensitive plants.

The earliest that you can plant onions in Smithfield 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. You probably don't want to wait any later than that or else your onions may not have a chance to really do well. Starting your onions indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost has passed is on March 15 in Smithfield. You can expect an average low temperature of 10°F in the coldest months of winter.

Since the USDA zone info for Smithfield is an average the actual date of last frost can change quite a bit from year to year. Half of the time in Smithfield you get a frost after March 15 so just be sure to be ready to protect your onions if you have a late frost.

USDA Zone Info for Smithfield

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

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

Plants to Grow in Smithfield

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