Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By referring to the USDA zone info for Ketchikan you should be able to estimate when you can plant zinnia.

Planting Calendar for Zinnia

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

Since zinnia do not do well in cold weather it's important to wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant zinnia in Ketchikan 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. If you are starting your zinnia indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Ketchikan. You should expect an average low temperature of 5°F in the coldest months of winter.

Keep in mind that USDA zone info for Ketchikan is not always accurate and the actual date of last frost will vary from year to year. Since half of the time in Ketchikan it frosts late in the year after April 15 be ready to cover your zinnia in the event of a surprise late frost.

USDA Zone Info for Ketchikan

Here is the info for USDA Zone 7b.

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

This means that on a really cold year, the coldest it will get is 5°F. On most years you should be prepared to experience lows near 10°F.

Plants to Grow in Ketchikan

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