One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You will be able to figure out when to plant dahlias by checking out the USDA zone info for Cortland.

Planting Calendar for Dahlias

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

It's not a good idea to plant dahlias until after the last frost has passed because they are not cold tolerant.

The earliest that you can plant dahlias in Cortland 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 few weeks earlier.

Last Frost Date

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

Just be sure to remember that USDA zone info for Cortland is an average and the actual date of last frost will vary from year to year. Since half of the time in Cortland you get a frost after April 15 be ready to cover your dahlias if you have a surprise late frost.

USDA Zone Info for Cortland

Here is the info for USDA Zone 5b.

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

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Cortland

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