One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first opportunity to plant tithonia in Ottawa can be figured out 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.

Since tithonia are not cold tolerant it's necessary to wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant tithonia in Ottawa 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. If you wait any later than that and your tithonia may not have a chance to fully mature. 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

The average date of last frost is April 15 in Ottawa. You can expect an average low temperature of -10°F in the coldest months of winter.

Just be sure to remember that USDA zone info for Ottawa is just an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in Ottawa you get surprised by a frost after April 15 be ready to protect your tithonia in the event of a late frost.

USDA Zone Info for Ottawa

Here is the info for USDA Zone 6a.

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

Plants to Grow in Ottawa

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