Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's possible to figure out when it's a good idea to plant tithonia by using the USDA zone info for Petersburg.

Planting Calendar for Tithonia

Frost tolerance for tithonia:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

You really shouldn't plant tithonia until after the last frost when the weather gets warmer because they are not cold tolerant.

The earliest that you can plant tithonia in Petersburg 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. You probably don't want to wait any later than that or else your tithonia may not have a chance to really do well. If you are starting your tithonia indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Petersburg the average date of last frost happens on April 15. It might get as low as 5°F during the coldest months of winter.

It's important to remember 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 Petersburg and it changes from year to year. Since half of the time in Petersburg you get a frost after April 15 be ready to cover your tithonia in the event of a late frost.

USDA Zone Info for Petersburg

Here is the info for USDA Zone 7b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	5°F
Highest Expected Low	10°F

This means that on a really cold year, the coldest it will get is 5°F. On most years you should be prepared to experience lows near 10°F.

Plants to Grow in Petersburg

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