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.

One way of making a decision about when it's a good idea to plant mimulus is to consult the USDA zone info for Watertown.

Planting Calendar for Mimulus

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

Mimulus require warm weather which means that you must wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant mimulus 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 mimulus and expect a good harvest is probably August. If you wait any later than that and your mimulus may not have a chance to grow to maturity. If you are starting your mimulus indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average all chance of frost has passed 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 may not be accurate from year to year the actual date of last frost is different every year. Since half of the time in Watertown it frosts late in the year after May 15 be ready to cover your mimulus 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.