When to Plant Coleus in Harrisburg, IL

One of the best tools that you have as gardeners to help us figure out 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 making a decision about when to plant coleus is to consult the USDA zone info for Harrisburg.


Planting Calendar for Coleus

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

Coleus are not cold tolerant which means that you have to wait until it warms up after all chance of frost has passed before you can plant them.

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

The earliest that you can plant coleus in Harrisburg is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant coleus and expect a good harvest is probably August. Any later than that and your coleus may not have a chance to fully mature. Starting your coleus indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Harrisburg. In the coldest months of winter you can expect an average low temperature of -5°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 Harrisburg and it is different every year. Since half of the time in Harrisburg it frosts late in the year after April 15 be ready to cover your coleus in the event of 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.