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.

You can figure out when it's a good idea to plant sweet williams in San Juan by reviewing the USDA zone info.

Planting Calendar for Sweet Williams

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

Sweet Williams do well in moderate cold which means that you can plant them a little bit earlier than more sensitive plants.

The earliest that you can plant sweet williams 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 sweet williams and expect a good harvest is probably October. Any later than that and your sweet williams may not have a chance to grow to maturity. Starting your sweet williams indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

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

Since the USDA zone info for San Juan may not be accurate from year to year the actual date of last frost is different every year. Half of the time in San Juan last frost occurs after February 15 so always be ready to cover your sweet williams if you have one of those late frosts.

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.