Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first chance to plant zinnia in Tualatin can be figured out by reviewing the USDA zone info.

Planting Calendar for Zinnia

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

Zinnia require warm weather which tells us that it's necessary to wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant zinnia in Tualatin 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 zinnia and expect a good harvest is probably August. Any later than that and your zinnia may not have a chance to grow to maturity. Starting your zinnia indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average all chance of frost has passed is on March 15 in Tualatin. It might get as low as 15°F during the coldest months of winter.

It's important to remember that USDA zone info for Tualatin may not be accurate from year to year and the actual date of last frost will vary from year to year. Since half of the time in Tualatin there is a last frost after March 15 be ready to cover your zinnia if you have a surprise late frost.

USDA Zone Info for Tualatin

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 Tualatin

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