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.

A common way of estimating when it's possible to plant dahlias is to refer to the USDA zone info for Delphos.

Planting Calendar for Dahlias

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

You really shouldn't plant dahlias until after all chance of frost has passed because they require warm weather.

The earliest that you can plant dahlias in Delphos 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. You probably don't want to wait any later than that or else your dahlias may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your dahlias indoors.

Last Frost Date

In Delphos the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -10°F.

Since the USDA zone info for Delphos is an average the actual date of last frost can change quite a bit from year to year. Half of the time in Delphos you get a frost after April 15 so just be sure to be ready to cover your dahlias in the event of a surprise late frost.

USDA Zone Info for Delphos

Here is the info for USDA Zone 6a.

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

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Delphos

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