The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You should be able to figure out when it's a good idea to plant campanula by looking at the USDA zone info for Holyoke.

Planting Calendar for Campanula

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

You can plant campanula a bit earlier in the year because they do well in moderate cold.

The earliest that you can plant campanula in Holyoke 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. Any later than that and your campanula may not have a chance to grow to maturity. Starting your campanula indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Holyoke the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -10°F.

Always 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 Holyoke and it is different every year. Since half of the time in Holyoke last frost occurs after April 15 be ready to protect your campanula if you have a late frost.

USDA Zone Info for Holyoke

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°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 -5°F.

Plants to Grow in Holyoke

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