Before planting it is a good idea to find your USDA Zone info to determine 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.

A common way of making a decision about when it's the best time to plant zinnia is to check out the USDA zone info for Wilsonville.

Planting Calendar for Zinnia

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

You should not plant zinnia until after the last frost has passed because they are not cold tolerant.

The earliest that you can plant zinnia in Wilsonville 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. If you wait any later than that and your zinnia may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your zinnia indoors.

Last Frost Date

In Wilsonville the average date of last frost happens on March 15. In the coldest months of winter you should expect an average low temperature of 15°F.

Keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Wilsonville and it can change quite a bit from year to year. Half of the time in Wilsonville there is a last frost after March 15 so make sure that you are prepared to cover your zinnia if you have a surprise late frost.

USDA Zone Info for Wilsonville

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 Wilsonville

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