The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first opportunity to plant coral bells in Waltham should be determined by using the USDA zone info.

Planting Calendar for Coral Bells

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

Coral Bells do well in moderate cold which tells us that you can get them planted earlier than other frost tender plants.

The earliest that you can plant coral bells in Waltham 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 coral bells and expect a good harvest is probably September. Any later than that and your coral bells may not have a chance to grow to maturity. You can get started a little bit earlier by starting your coral bells indoors.

Last Frost Date

The average date of last frost is April 15 in Waltham. In the coldest months of winter you can expect an average low temperature of -10°F.

Just be sure to remember that the actual date of last frost is an average because it is based on the USDA zone info for Waltham and it will vary from year to year. Since half of the time in Waltham it frosts late in the year after April 15 be ready to protect your coral bells in the event of a late frost.

USDA Zone Info for Waltham

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 Waltham

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