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.

In Swarthmore you can estimate when you can plant phlox by looking at the USDA zone info.

Planting Calendar for Phlox

Frost tolerance for phlox:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

You can plant phlox a little earlier in the year because they are moderately cold tolerant.

The earliest that you can plant phlox in Swarthmore is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant phlox and expect a good harvest is probably September. If you wait any later than that and your phlox may not have a chance to grow to maturity. If you are starting your phlox 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 Swarthmore. You can expect an average low temperature of 0°F in the coldest months of winter.

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