One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Houston you can estimate when it's possible to plant gladiolus by using the USDA zone info.

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.

You can plant gladiolus a bit earlier in the year because they do ok in moderate cold.

The earliest that you can plant gladiolus in Houston 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. If you wait 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

In Houston the average date of last frost happens on February 15. It might get as low as 20°F during the coldest months of winter.

Keep in mind that USDA zone info for Houston is just an average and the actual date of last frost is different every year. Since half of the time in Houston it frosts late in the year after February 15 be ready to protect your gladiolus if you have a late frost.

USDA Zone Info for Houston

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°F

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

Plants to Grow in Houston

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