Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The best time to plant phlox in Riverdale should be estimated by reviewing 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.

Phlox can survive in moderate cold which means that you can plant them a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant phlox in Riverdale 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. Any later than that and your phlox may not have a chance to fully mature. Starting your phlox indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Riverdale. In the coldest months of winter you should expect an average low temperature of -10°F.

Since the USDA zone info for Riverdale is not always accurate the actual date of last frost is different every year. Since half of the time in Riverdale it frosts late in the year after April 15 be ready to protect your phlox in the event of a surprise late frost.

USDA Zone Info for Riverdale

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 Riverdale

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