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.

A way of making a decision about when it's a good idea to plant gladiolus is to consult the USDA zone info for Collinsville.

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.

Gladiolus are barely cold tolerant which tells us that you can get them planted just a bit earlier than other plants that might not handle the cold.

The earliest that you can plant gladiolus in Collinsville 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. 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 April 15 in Collinsville. You can expect an average low temperature of -5°F in the coldest months of winter.

Just be sure to remember that USDA zone info for Collinsville is just an average and the actual date of last frost changes from year to year. Half of the time in Collinsville you get surprised by a frost after April 15 so be sure to be ready to cover your gladiolus if you have one of those late frosts.

USDA Zone Info for Collinsville

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 Low	0°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 Collinsville

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