The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Detroit you can determine when it's the best time to plant sunflowers by checking out the USDA zone info.

Planting Calendar for Sunflowers

Frost tolerance for sunflowers:	Not tolerant of frost.
When to plant:	After the last frost has passed.

It's probably a bad idea to plant sunflowers until after the last frost when the weather gets warmer because they are not cold tolerant.

The earliest that you can plant sunflowers in Detroit 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 sunflowers and expect a good harvest is probably August. You probably don't want to wait any later than that or else your sunflowers may not have a chance to really do well. You can get started a couple of weeks earlier by starting your sunflowers indoors.

Last Frost Date

In Detroit the average date of last frost happens on April 15. It might get as low as -5°F during the coldest months of winter.

Always keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Detroit and it changes from year to year. Half of the time in Detroit you get a frost after April 15 so make sure that you are ready to cover your sunflowers in the event of a surprise late frost.

USDA Zone Info for Detroit

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 Detroit

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