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.

In Philadelphia you can estimate when it's the best time to plant tithonia by referring to the USDA zone info.

Planting Calendar for Tithonia

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

Tithonia require warm weather which means that you really should wait until it warms up after the last frost before you can plant them.

The earliest that you can plant tithonia in Philadelphia 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. You can get started a couple of weeks earlier by starting your tithonia indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Philadelphia. It might get as low as 0°F during the coldest months of winter.

Just be sure to remember that USDA zone info for Philadelphia is not always accurate and the actual date of last frost will vary from year to year. Since half of the time in Philadelphia last frost occurs after April 15 be ready to cover your tithonia if you have a late frost.

USDA Zone Info for Philadelphia

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Philadelphia

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