The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. 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 can be reviewed to determine when it's a good idea to plant sweet williams.

Planting Calendar for Sweet Williams

Frost tolerance for sweet williams:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Since sweet williams are one of those plants that can tolerate a little bit of cold weather you can plant them a little bit earlier in the year than other frost tender plants.

The earliest that you can plant sweet williams 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 sweet williams and expect a good harvest is probably September. If you wait any later than that and your sweet williams may not have a chance to grow to maturity. You can get started a little bit earlier by starting your sweet williams indoors.

Last Frost Date

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

Since the USDA zone info for Smithfield may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Since half of the time in Smithfield you get a frost after April 15 be ready to protect your sweet williams if you have one of those late frosts.

USDA Zone Info for Smithfield

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 Smithfield

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