One of the first steps you take when you are getting a good idea 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.

The first chance to plant phlox in Williston can be figured out 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.

Since phlox are moderately cold tolerant you can plant them just a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant phlox in Williston 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. Any later than that and 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 Williston the average date of last frost happens on May 15. You can expect an average low temperature of -30°F in the coldest months of winter.

Keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Williston and it can change quite a bit from year to year. Half of the time in Williston you get a frost after May 15 so make sure that you are prepared to cover your phlox if you have a surprise late frost.

USDA Zone Info for Williston

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Williston

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