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.

The USDA zone info for Portage should be looked at to determine when to plant zinnia.

Planting Calendar for Zinnia

Frost tolerance for zinnia:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Zinnia require warm weather which means that you really should wait until it warms up after the last frost before you can plant them.

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. If you wait 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

The average date of last frost is April 15 in Portage. It might get as low as -20°F during the coldest months of winter.

Since the USDA zone info for Portage is just an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Portage you get a frost after April 15 be ready to cover your zinnia in the event of a surprise late frost.

USDA Zone Info for Portage

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Portage

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