One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first opportunity to plant campanula in Holmen can be figured out by checking out the USDA zone info.

Planting Calendar for Campanula

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

Campanula are one of those plants that can tolerate a little bit of cold weather which tells us that you can plant them a little bit earlier than more sensitive plants.

The earliest that you can plant campanula in Holmen 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 campanula and expect a good harvest is probably August. 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 little bit earlier.

Last Frost Date

On average the last frost is on May 15 in Holmen. It might get as low as -25°F during the coldest months of winter.

Since the USDA zone info for Holmen may not be accurate from year to year the actual date of last frost changes from year to year. Half of the time in Holmen it frosts late in the year after May 15 so make sure that you are prepared to protect your campanula if you have a late frost.

USDA Zone Info for Holmen

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°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 -20°F.

Plants to Grow in Holmen

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