One of the best tools that you have as gardeners to help us determine 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.

The USDA zone info for Rochester should be read to determine when it's a good idea to plant gladiolus.

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 means that you can plant them slightly earlier than plants that are more sensitive to the cold.

The earliest that you can plant gladiolus in Rochester 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. If you wait 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 couple of weeks earlier.

Last Frost Date

On average the last frost is on May 15 in Rochester. You can expect an average low temperature of -25°F in the coldest months of winter.

Remember that USDA zone info for Rochester is not always accurate and the actual date of last frost will vary from year to year. Half of the time in Rochester you get surprised by a frost after May 15 so make sure that you are prepared to cover your gladiolus in the event of one of those late frosts.

USDA Zone Info for Rochester

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Rochester

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