One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The earliest that you can plant dahlias in Swarthmore can be determined by checking out the USDA zone info.

Planting Calendar for Dahlias

Frost tolerance for dahlias:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Dahlias require warm weather which tells us that it is important to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant dahlias in Swarthmore 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 fully mature. You can get started a couple of weeks earlier by starting your dahlias indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Swarthmore. It might get as low as 0°F during the coldest months of winter.

Since the USDA zone info for Swarthmore is an average the actual date of last frost can change quite a bit from year to year. Half of the time in Swarthmore you get surprised by a frost after April 15 so just be sure to be ready to cover your dahlias if you have one of those late frosts.

USDA Zone Info for Swarthmore

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 Swarthmore

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