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 using the USDA zone info for Houghton it's possible to figure out 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.

Since campanula are one of those plants that can tolerate a little bit of cold weather you can plant them just a bit earlier in the year than other frost tender plants.

The earliest that you can plant campanula in Houghton 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 grow to maturity. If you are starting your campanula indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Houghton the average date of last frost happens on April 15. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Houghton is just an average the actual date of last frost is different every year. Half of the time in Houghton you get surprised by a frost after April 15 so make sure that you are ready to protect your campanula in the event of a late frost.

USDA Zone Info for Houghton

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

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

Plants to Grow in Houghton

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