One of the best tools that you have as gardeners to help us determine 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.

One way of getting a good idea when it's possible to plant lobelia is to consult the USDA zone info for Petersburg.

Planting Calendar for Lobelia

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

Lobelia are very cold tolerant which tells us that you can plant them a quite a bit earlier than other plants that might not handle the cold.

The earliest that you can plant lobelia in Petersburg is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant lobelia and expect a good harvest is probably September. Any later than that and your lobelia may not have a chance to fully mature. Starting your lobelia indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Petersburg. You should expect an average low temperature of 5°F in the coldest months of winter.

It's important to remember that USDA zone info for Petersburg is not always accurate and the actual date of last frost changes from year to year. Half of the time in Petersburg you get surprised by a frost after April 15 so make sure that you are ready to protect your lobelia in the event of a surprise late frost.

USDA Zone Info for Petersburg

Here is the info for USDA Zone 7b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	5°F
Highest Expected Low	10°F

This means that on a really cold year, the coldest it will get is 5°F. On most years you should be prepared to experience lows near 10°F.

Plants to Grow in Petersburg

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