One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

It's possible to estimate when you can plant zinnia by referring to the USDA zone info for Grand Rapids.

Planting Calendar for Zinnia

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

Since zinnia are not cold tolerant it is important to wait until after the last frost before you can plant them.

The earliest that you can plant zinnia in Grand Rapids is May. However, you really should wait until June 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 couple of weeks earlier by starting your zinnia indoors.

Last Frost Date

On average the last frost has passed is on May 15 in Grand Rapids. You can expect an average low temperature of -35°F in the coldest months of winter.

Keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Grand Rapids and it will vary from year to year. Since half of the time in Grand Rapids you get surprised by a frost after May 15 be ready to cover your zinnia if you have a surprise late frost.

USDA Zone Info for Grand Rapids

Here is the info for USDA Zone 3b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-35°F
Highest Expected Low	-30°F

This means that on a really cold year, the coldest it will get is -35°F. On most years you should be prepared to experience lows near -30°F.

Plants to Grow in Grand Rapids

You may be interested in your other planting guides for Grand Rapids.