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.

It's a good idea to figure out when to plant trifolium by using the USDA zone info for Petaluma.

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.

Since trifolium are one of those plants that can tolerate a tiny bit of cold weather you can plant them just a tiny bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant trifolium in Petaluma 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. If you wait any later than that and your trifolium may not have a chance to really do well. You can get started a little bit earlier by starting your trifolium indoors.

Last Frost Date

The average date of last frost is February 15 in Petaluma. In the coldest months of winter you can expect an average low temperature of 25°F.

Keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Petaluma and it is different every year. Since half of the time in Petaluma last frost occurs after February 15 be ready to protect your trifolium if you have a surprise late frost.

USDA Zone Info for Petaluma

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 Petaluma

You may be interested in your other planting guides for Petaluma.