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

By looking at the USDA zone info for Watertown you should be able to figure out when you can plant trifolium.

Planting Calendar for Trifolium

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

Trifolium are one of those plants that can tolerate a tiny bit of cold weather which tells us that you can plant them slightly earlier than more sensitive plants.

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

The last month that you can plant trifolium and expect a good harvest is probably August. Any later than that and your trifolium may not have a chance to fully mature. Starting your trifolium indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Watertown. It might get as low as -20°F during the coldest months of winter.

It's important to remember that USDA zone info for Watertown is an average and the actual date of last frost changes from year to year. Since half of the time in Watertown you get a frost after April 15 be ready to protect your trifolium if you have a late frost.

USDA Zone Info for Watertown

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Watertown

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