Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first chance to plant lobelia in Watertown should be estimated by using the USDA zone info.

Planting Calendar for Lobelia

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

Lobelia do well in pretty solid cold which tells us that you can plant them quite a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant lobelia 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 lobelia and expect a good harvest is probably August. If you wait any later than that and your lobelia may not have a chance to fully mature. If you are starting your lobelia indoors then you might be able to get away with starting them a little bit 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 -30°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 there is a last frost after May 15 be ready to cover your lobelia in the event of a late frost.

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.