Before planting it is a good idea to find your USDA Zone info to figure out 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.

In Worthington you can estimate when it's possible to plant dahlias by referring to the USDA zone info.

Planting Calendar for Dahlias

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

Dahlias are not cold tolerant which means that you must wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant dahlias in Worthington 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 dahlias and expect a good harvest is probably August. Any later than that and your dahlias may not have a chance to fully mature. If you are starting your dahlias indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is May 15 in Worthington. You can expect an average low temperature of -25°F in the coldest months of winter.

Since the USDA zone info for Worthington may not be accurate from year to year the actual date of last frost is different every year. Half of the time in Worthington there is a last frost after May 15 so always be ready to cover your dahlias in the event of one of those late frosts.

USDA Zone Info for Worthington

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Worthington

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