The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You should be able to determine when it's a good idea to plant sunflowers by using the USDA zone info for Willoughby.

Planting Calendar for Sunflowers

Frost tolerance for sunflowers:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Sunflowers are not cold tolerant which tells us that you really should wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant sunflowers in Willoughby 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 grow to maturity. If you are starting your sunflowers indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Willoughby. In the coldest months of winter you should expect an average low temperature of -5°F.

Keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Willoughby and it can change quite a bit from year to year. Half of the time in Willoughby it frosts late in the year after April 15 so make sure that you are ready to cover your sunflowers in the event of a late frost.

USDA Zone Info for Willoughby

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 Willoughby

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