The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You should be able to determine when you can plant bittercress by checking out the USDA zone info for Watertown.

Planting Calendar for Bittercress

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

Bittercress do ok in moderate cold which means that you can plant them slightly earlier than other frost tender plants.

The earliest that you can plant bittercress 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 bittercress and expect a good harvest is probably August. You probably don't want to wait any later than that or else your bittercress may not have a chance to really do well. If you are starting your bittercress indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is May 15 in Watertown. It might get as low as -30°F during the coldest months of winter.

It's important to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Watertown and it will vary from year to year. Half of the time in Watertown there is a last frost after May 15 so just be sure to be ready to protect your bittercress 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.