The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Colby should be reffered to in order to determine when it's possible to plant dianthus.

Planting Calendar for Dianthus

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

Since dianthus are one of those plants that can tolerate a little bit of cold weather you can plant them just a bit earlier in the year than other frost tender plants.

The earliest that you can plant dianthus in Colby 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 dianthus and expect a good harvest is probably September. You probably don't want to wait any later than that or else your dianthus may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your dianthus indoors.

Last Frost Date

On average the last frost is on April 15 in Colby. You should expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Colby may not be accurate from year to year the actual date of last frost is different every year. Since half of the time in Colby last frost occurs after April 15 be ready to cover your dianthus if you have one of those late frosts.

USDA Zone Info for Colby

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 Colby

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