Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first opportunity to plant dahlias in Harrisburg should be figured out by checking out the USDA zone info.

Planting Calendar for Dahlias

Frost tolerance for dahlias:	Not tolerant of frost.
When to plant:	After the last frost.

Since dahlias are not cold tolerant it's important to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant dahlias 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 dahlias and expect a good harvest is probably August. If you wait any later than that and your dahlias may not have a chance to really do well. Starting your dahlias indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Harrisburg the average date of last frost happens on April 15. You should expect an average low temperature of 5°F in the coldest months of winter.

Since the USDA zone info for Harrisburg may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in Harrisburg there is a last frost after April 15 so make sure that you are ready to cover your dahlias in the event of a late frost.

USDA Zone Info for Harrisburg

Here is the info for USDA Zone 7b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	5°F
Highest Expected Low	10°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 10°F.

Plants to Grow in Harrisburg

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