One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Watertown should be reffered to in order to figure out when it's the best time to plant nigella.

Planting Calendar for Nigella

Frost tolerance for nigella:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Nigella tend to make it in pretty solid cold which tells us that you can plant them much earlier in the year than other frost tender plants.

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

Last Frost Date

On average all chance of frost has passed is on May 15 in Watertown. It might get as low as -30°F during the coldest months of winter.

Since the USDA zone info for Watertown is not always accurate the actual date of last frost is different every year. Since half of the time in Watertown you get a frost after May 15 be ready to cover your nigella in the event of 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.