Before planting it is a good idea to find your USDA Zone info to estimate 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.

One way of figuring out when to plant dianthus is to use the USDA zone info for Houston.

Planting Calendar for Dianthus

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

Dianthus are one of those plants that can tolerate a little bit of cold weather which tells us that you can start planting them earlier than more sensitive plants.

The earliest that you can plant dianthus in Houston is January. However, you really should wait until February if you don't want to take any chances.

The last month that you can plant dianthus and expect a good harvest is probably October. Any later than that and your dianthus may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your dianthus indoors.

Last Frost Date

On average all chance of frost has passed is on February 15 in Houston. In the coldest months of winter you can expect an average low temperature of 20°F.

Keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Houston and it changes from year to year. Since half of the time in Houston last frost occurs after February 15 be ready to cover your dianthus if you have one of those late frosts.

USDA Zone Info for Houston

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°F

This means that on a really cold year, the coldest it will get is 20°F. On most years you should be prepared to experience lows near 25°F.

Plants to Grow in Houston

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