One of the best tools that you have as gardeners to help us determine 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 determining when it's a good idea to plant gladiolus is to check out the USDA zone info for Tucson.

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 are barely cold tolerant 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 Tucson is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant gladiolus and expect a good harvest is probably September. You probably don't want to wait any later than that or else your gladiolus may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your gladiolus indoors.

Last Frost Date

On average the last frost has passed is on February 15 in Tucson. It might get as low as 25°F during the coldest months of winter.

Since the USDA zone info for Tucson is not always accurate the actual date of last frost will vary from year to year. Half of the time in Tucson it frosts late in the year after February 15 so make sure that you are prepared to cover your gladiolus in the event of a surprise late frost.

USDA Zone Info for Tucson

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°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 30°F.

Plants to Grow in Tucson

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