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.

By checking out the USDA zone info for Portsmouth it's a good idea to figure out when it's possible to plant tithonia.

Planting Calendar for Tithonia

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

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

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

Last Frost Date

In Portsmouth the average date of last frost happens on March 15. It might get as low as 10°F during the coldest months of winter.

Since the USDA zone info for Portsmouth is not always accurate the actual date of last frost will vary from year to year. Since half of the time in Portsmouth it frosts late in the year after March 15 be ready to protect your tithonia in the event of a surprise late frost.

USDA Zone Info for Portsmouth

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

This means that on a really cold year, the coldest it will get is 10°F. On most years you should be prepared to experience lows near 15°F.

Plants to Grow in Portsmouth

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