One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. 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 Harper Woods it's a good idea to determine when it's the best time 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 a bad idea to plant zinnia until after all chance of frost has passed because they are not cold tolerant.

The earliest that you can plant zinnia in Harper Woods 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 few weeks earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Harper Woods. In the coldest months of winter you can expect an average low temperature of -5°F.

Just be sure to remember that the actual date of last frost is an average because it is based on the USDA zone info for Harper Woods and it can change quite a bit from year to year. Half of the time in Harper Woods last frost occurs after April 15 so make sure that you are prepared to protect your zinnia in the event of a late frost.

USDA Zone Info for Harper Woods

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°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 0°F.

Plants to Grow in Harper Woods

You may be interested in your other planting guides for Harper Woods.