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 referring to the USDA zone info for Suisun City it's a good idea to figure out when to plant trifolium.

Planting Calendar for Trifolium

Frost tolerance for trifolium:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Trifolium do ok in moderate cold which tells us that you can plant them slightly earlier than plants that are more sensitive to the cold.

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

The last month that you can plant trifolium and expect a good harvest is probably September. You probably don't want to wait any later than that or else your trifolium may not have a chance to grow to maturity. You can get started a little bit earlier by starting your trifolium indoors.

Last Frost Date

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

Since the USDA zone info for Suisun City may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Since half of the time in Suisun City there is a last frost after February 15 be ready to cover your trifolium if you have 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.