One of the first steps you take when you are getting a good idea your gardening schedule is find your 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.

By using the USDA zone info for Watertown you should be able to estimate when it's the best time to plant alternaria.

Planting Calendar for Alternaria

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

It's a bad idea to plant alternaria until after the last frost when the weather gets warmer because they require warm weather.

The earliest that you can plant alternaria 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 alternaria and expect a good harvest is probably August. If you wait any later than that and your alternaria may not have a chance to fully mature. If you are starting your alternaria indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Watertown the average date of last frost happens on May 15. In the coldest months of winter you can expect an average low temperature of -25°F.

Keep in mind that USDA zone info for Watertown is an average and the actual date of last frost will vary from year to year. Since half of the time in Watertown there is a last frost after May 15 be ready to cover your alternaria in the event of a late frost.

USDA Zone Info for Watertown

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Watertown

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