One of the best tools that you have as gardeners to help us estimate 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.

The first chance to plant phlox in Zone 3a can be estimated by referring to 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 are one of those plants that can tolerate a little bit of cold weather which tells us that you can plant them earlier than more sensitive plants.

The earliest that you can plant phlox in Zone 3a is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant phlox and expect a good harvest is probably August. You probably don't want to wait any later than that or else your phlox may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your phlox indoors.

Last Frost Date

In Zone 3a the average date of last frost happens on May 15. In the coldest months of winter you can expect an average low temperature of -40°F.

Since the USDA zone info for Zone 3a is not always accurate the actual date of last frost changes from year to year. Half of the time in Zone 3a you get a frost after May 15 so just be sure to be ready to cover your phlox in the event of a surprise late frost.

USDA Zone Info for Zone 3a

Here is the info for USDA Zone 3a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-40°F
Highest Expected Low	-35°F

This means that on a really cold year, the coldest it will get is -40°F. On most years you should be prepared to experience lows near -35°F.

Plants to Grow in Zone 3a

You may be interested in your other planting guides for Zone 3a.