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.

One way of making a decision about when you can plant tithonia is to consult the USDA zone info for Lake Oswego.

Planting Calendar for Tithonia

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

You really shouldn't plant tithonia until after all chance of frost has passed because they are not cold tolerant.

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

Last Frost Date

The average date of last frost is March 15 in Lake Oswego. It might get as low as 15°F during the coldest months of winter.

Keep in mind that USDA zone info for Lake Oswego is an average and the actual date of last frost changes from year to year. Half of the time in Lake Oswego it frosts late in the year after March 15 so always be ready to cover your tithonia in the event of one of those late frosts.

USDA Zone Info for Lake Oswego

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°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 20°F.

Plants to Grow in Lake Oswego

You may be interested in your other planting guides for Lake Oswego.