When to Plant Gladiolus in Harrisburg, PA

One of the first steps you take when you are determining your gardening schedule is find your 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.

The earliest that you can plant gladiolus in Harrisburg can be figured out by referring to the USDA zone info.


Planting Calendar for Gladiolus

Frost tolerance for gladiolus: Tolerant of a very small amount of frost.
When to plant: Up to 3 weeks before last frost.

You can plant gladiolus slightly earlier in the year because they do ok in moderate cold.

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

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

Last Frost Date

In Harrisburg the average date of last frost happens on April 15. You should expect an average low temperature of 0°F in the coldest months of winter.

Keep in mind that USDA zone info for Harrisburg is not always accurate and the actual date of last frost changes from year to year. Since half of the time in Harrisburg you get a frost after April 15 be ready to protect your gladiolus in the event of one of those late frosts.

USDA Zone Info for Harrisburg

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low0°F
Highest Expected Low5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Harrisburg

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