One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A common way of estimating when to plant gladiolus is to use the USDA zone info for Harvard.

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.

Since gladiolus do ok in moderate cold you can plant them just a tiny bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant gladiolus in Harvard 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. You probably don't want to wait any later than that or else your gladiolus may not have a chance to grow to maturity. Starting your gladiolus indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Harvard. In the coldest months of winter you should expect an average low temperature of -15°F.

Remember that USDA zone info for Harvard is an average and the actual date of last frost will vary from year to year. Since half of the time in Harvard it frosts late in the year after April 15 be ready to cover your gladiolus in the event of one of those late frosts.

USDA Zone Info for Harvard

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Harvard

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