The USDA Zone info is a great tool for gardeners to help us figure out 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.

In Smithfield you can determine when you can plant pyrethrum by using the USDA zone info.

Planting Calendar for Pyrethrum

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

Pyrethrum do ok in some cold which means that you can plant them a little bit earlier in the year than other frost tender plants.

The earliest that you can plant pyrethrum 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 pyrethrum and expect a good harvest is probably September. Any later than that and your pyrethrum may not have a chance to really do well. You can get started a couple of weeks earlier by starting your pyrethrum indoors.

Last Frost Date

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

Always keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Smithfield and it is different every year. Half of the time in Smithfield you get a frost after April 15 so always be ready to cover your pyrethrum in the event of a surprise late frost.

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.