One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

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

Planting Calendar for Dahlias

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

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

The earliest that you can plant dahlias in Gaithersburg 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. Any later than that and your dahlias may not have a chance to really do well. If you are starting your dahlias indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Gaithersburg. You should expect an average low temperature of 0°F in the coldest months of winter.

Just be sure to remember that USDA zone info for Gaithersburg may not be accurate from year to year and the actual date of last frost changes from year to year. Half of the time in Gaithersburg 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 Gaithersburg

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 Gaithersburg

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