One of the best tools that you have as gardeners to help us estimate your gardening schedule is the 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 chance to plant portulaca in Watertown can be determined by checking out the USDA zone info.

Planting Calendar for Portulaca

Frost tolerance for portulaca:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Portulaca do not do well in cold weather which means that you need to wait until it warms up after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant portulaca 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 portulaca and expect a good harvest is probably August. Any later than that and your portulaca may not have a chance to really do well. You can get started a little bit earlier by starting your portulaca indoors.

Last Frost Date

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

Remember that USDA zone info for Watertown may not be accurate from year to year and 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 portulaca in the event of a late frost.

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.