One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By looking at the USDA zone info for Suisun City you should be able to determine when it's possible to plant heliotrope.

Planting Calendar for Heliotrope

Frost tolerance for heliotrope:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Heliotrope are not cold tolerant which means that you must wait until it warms up after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant heliotrope in Suisun City is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant heliotrope and expect a good harvest is probably September. Any later than that and your heliotrope may not have a chance to really do well. Starting your heliotrope indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost is on February 15 in Suisun City. You should expect an average low temperature of 25°F in the coldest months of winter.

Since the USDA zone info for Suisun City is just an average the actual date of last frost changes from year to year. Half of the time in Suisun City it frosts late in the year after February 15 so always be ready to protect your heliotrope in the event of a surprise late frost.

USDA Zone Info for Suisun City

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 Suisun City

You may be interested in your other planting guides for Suisun City.