Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You will be able to figure out when you can plant purple bell vines by checking out the USDA zone info for Watertown.

Planting Calendar for Purple Bell Vines

Frost tolerance for purple bell vines:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Purple Bell Vines can survive in a tiny bit of cold which means that you can plant them just a tiny bit earlier in the year than more sensitive plants.

The earliest that you can plant purple bell vines in Watertown is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant purple bell vines and expect a good harvest is probably August. You probably don't want to wait any later than that or else your purple bell vines may not have a chance to grow to maturity. If you are starting your purple bell vines indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

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

Since the USDA zone info for Watertown is not always accurate the actual date of last frost changes from year to year. Since half of the time in Watertown last frost occurs after May 15 be ready to protect your purple bell vines if you have a surprise late frost.

USDA Zone Info for Watertown

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 Watertown

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