One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The earliest that you can plant jerusalem artichokes in San Juan should be figured out by referring to the USDA zone info.

Planting Calendar for Jerusalem artichokes

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

Jerusalem artichokes do ok in mild cold which tells us that you can plant them a bit earlier in the year than other frost tender plants.

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

Last Frost Date

In San Juan the average date of last frost happens on February 15. It might get as low as 25°F during the coldest months of winter.

Just be sure to remember that the actual date of last frost is an average because it is based on the USDA zone info for San Juan and it changes from year to year. Half of the time in San Juan there is a last frost after February 15 so just be sure to be ready to protect your jerusalem artichokes if you have 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.