When can I plant Gladiolus in Zone 4a

One of the best tools that we have as gardeners to help us figure out our 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 our area.

By reviewing the USDA zone info for Zone 4a you should be able to estimate when it's the best time to plant gladiolus.


Planting Calendar for Gladiolus

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

You can plant gladiolus a bit earlier in the year because they are barely cold tolerant.

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 Zone 4a 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 gladiolus and expect a good harvest is probably August. Any later than that and your gladiolus may not have a chance to really do well. If you are starting your gladiolus indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is May 15 in Zone 4a. In the coldest months of winter we should expect an average low temperature of -30°F.

Remember that our actual date of last frost is an average because it is based on the USDA zone info for Zone 4a and it can change quite a bit from year to year. Half of the time in Zone 4a last frost occurs after May 15 so always be ready to protect your gladiolus in the event of one of those late frosts.

USDA Zone Info for Zone 4a

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 Zone 4a

You may be interested in our other planting guides for Zone 4a.