One of the first steps you take when you are figuring out 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.

One way of determining when it's possible to plant phlox is to use the USDA zone info for Littleton.

Planting Calendar for Phlox

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

Since phlox are one of those plants that can tolerate a little bit of cold weather 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 Littleton 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. 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

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

Since the USDA zone info for Littleton is an average the actual date of last frost will vary from year to year. Half of the time in Littleton it frosts late in the year after April 15 so always be ready to protect your phlox in the event of a surprise late frost.

USDA Zone Info for Littleton

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Littleton

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