One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By reviewing the USDA zone info for Portage you should be able to figure out when it's a good idea to plant zinnia.

Planting Calendar for Zinnia

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

It's probably not a good idea to plant zinnia until after the last frost has passed because they do not do well in cold weather.

The earliest that you can plant zinnia in Portage 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. You can get started a few weeks earlier by starting your zinnia indoors.

Last Frost Date

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

Since the USDA zone info for Portage is an average the actual date of last frost changes from year to year. Half of the time in Portage you get surprised by a frost after April 15 so make sure that you are ready to protect your zinnia if you have a late frost.

USDA Zone Info for Portage

Here is the info for USDA Zone 5b.

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

Plants to Grow in Portage

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