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

The first chance to plant dahlia in Watertown can be determined by checking out the USDA zone info.

Planting Calendar for Dahlia

Frost tolerance for dahlia:	Not tolerant of frost.
When to plant:	After the last frost.

Dahlia are not cold tolerant which tells us that you have to wait until it warms up after the last frost before you can plant them.

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

The last month that you can plant dahlia and expect a good harvest is probably August. Any later than that and your dahlia may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your dahlia indoors.

Last Frost Date

On average the last frost is on May 15 in Watertown. In the coldest months of winter you can expect an average low temperature of -30°F.

Since the USDA zone info for Watertown is just an average the actual date of last frost is different every year. Half of the time in Watertown it frosts late in the year after May 15 so be sure to be ready to protect your dahlia if you have one of those late frosts.

USDA Zone Info for Watertown

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Watertown

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