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.

The USDA zone info for Santa Clara can be used to estimate when it's the best time to plant campanula.

Planting Calendar for Campanula

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

Campanula are moderately cold tolerant which tells us that you can plant them earlier than plants that are more sensitive to the cold.

The earliest that you can plant campanula in Santa Clara 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 campanula and expect a good harvest is probably September. If you wait any later than that and your campanula may not have a chance to really do well. Starting your campanula indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is March 15 in Santa Clara. You should expect an average low temperature of 10°F in the coldest months of winter.

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 Santa Clara and it can change quite a bit from year to year. Since half of the time in Santa Clara you get surprised by a frost after March 15 be ready to cover your campanula if you have one of those late frosts.

USDA Zone Info for Santa Clara

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

This means that on a really cold year, the coldest it will get is 10°F. On most years you should be prepared to experience lows near 15°F.

Plants to Grow in Santa Clara

You may be interested in your other planting guides for Santa Clara.