Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can figure out when you can plant sunflowers in Harrisburg by referring to the USDA zone info.

Planting Calendar for Sunflowers

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

You can not plant sunflowers until after the last frost when the weather gets warmer because they require warm weather.

The earliest that you can plant sunflowers in Harrisburg 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. Any later than that and your sunflowers may not have a chance to grow to maturity. Starting your sunflowers indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Harrisburg the average date of last frost happens on April 15. You should expect an average low temperature of 0°F in the coldest months of winter.

Keep in mind that USDA zone info for Harrisburg is just an average and the actual date of last frost changes from year to year. Half of the time in Harrisburg you get surprised by a frost after April 15 so always be ready to cover your sunflowers if you have one of those late frosts.

USDA Zone Info for Harrisburg

Here is the info for USDA Zone 7a.

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

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Harrisburg

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