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.

The USDA zone info for Watertown should be reffered to in order to estimate when you can plant streptocarpella.

Planting Calendar for Streptocarpella

Frost tolerance for streptocarpella:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Since streptocarpella are not cold tolerant you have to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant streptocarpella 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 streptocarpella and expect a good harvest is probably August. Any later than that and your streptocarpella may not have a chance to grow to maturity. Starting your streptocarpella indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Watertown. In the coldest months of winter you should expect an average low temperature of -25°F.

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. Since half of the time in Watertown last frost occurs after May 15 be ready to protect your streptocarpella in the event of one of those late frosts.

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.