The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The best time to plant dianthus in San Juan should be estimated by looking at the USDA zone info.

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 a little bit earlier in the year than other frost tender plants.

The earliest that you can plant dianthus in San Juan 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. You probably don't want to wait any later than that or else your dianthus may not have a chance to grow to maturity. If you are starting your dianthus indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is February 15 in San Juan. You can expect an average low temperature of 25°F in the coldest months of winter.

Since the USDA zone info for San Juan is not always accurate the actual date of last frost is different every year. Since half of the time in San Juan last frost occurs after February 15 be ready to cover your dianthus in the event of a late frost.

USDA Zone Info for San Juan

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

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

Plants to Grow in San Juan

You may be interested in your other planting guides for San Juan.