When to Plant Lobelia in Harrisburg, IL

The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Harrisburg you can determine when to plant lobelia by reviewing 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.

You can plant lobelia quite a bit earlier in the year because they do well in cold.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant lobelia
Possibly ok, but a risky time to plant lobelia
Probably not a good time to plant lobelia

The earliest that you can plant lobelia in Harrisburg 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. If you wait any later than that and your lobelia may not have a chance to really do well. Starting your lobelia indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Harrisburg. It might get as low as -5°F during the coldest months of winter.

Since the USDA zone info for Harrisburg is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in Harrisburg there is a last frost after April 15 so just be sure to be ready to cover your lobelia if you have one of those late frosts.

USDA Zone Info for Harrisburg

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low-5°F
Highest Expected Low0°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 0°F.

Plants to Grow in Harrisburg

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