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

You will be able to determine when you can plant tithonia by referring to the USDA zone info for Smithfield.

Planting Calendar for Tithonia

Frost tolerance for tithonia:	Not tolerant of frost.
When to plant:	After the last frost.

Tithonia are not cold tolerant which tells us that you need to wait until it warms up after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant tithonia in Smithfield is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant tithonia and expect a good harvest is probably August. Any later than that and your tithonia may not have a chance to grow to maturity. If you are starting your tithonia indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

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

Always keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Smithfield and it can change quite a bit from year to year. Half of the time in Smithfield you get surprised by a frost after April 15 so just be sure to be ready to protect your tithonia in the event of 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.