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.

It's a good idea to figure out when it's a good idea to plant gladiolus by referring to the USDA zone info for San Ramon.

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 one of those plants that can tolerate a tiny bit of cold weather which means that you can start planting them slightly earlier than more sensitive plants.

The earliest that you can plant gladiolus in San Ramon 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. Any later than that and your gladiolus may not have a chance to really do well. Starting your gladiolus indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is February 15 in San Ramon. It might get as low as 25°F during the coldest months of winter.

Since the USDA zone info for San Ramon is not always accurate the actual date of last frost is different every year. Half of the time in San Ramon you get surprised by a frost after February 15 so just be sure to be ready to cover your gladiolus if you have one of those late frosts.

USDA Zone Info for San Ramon

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 San Ramon

You may be interested in your other planting guides for San Ramon.