One of the first steps you take when you are getting a good idea 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.

The USDA zone info for Philadelphia can be reffered to in order to estimate 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 do ok in moderate cold which means that you can start planting them slightly earlier than other frost tender plants.

The earliest that you can plant gladiolus in Philadelphia 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. If you wait any later than that and your gladiolus may not have a chance to grow to maturity. Starting your gladiolus indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Philadelphia the average date of last frost happens on March 15. In the coldest months of winter you can expect an average low temperature of 10°F.

Keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Philadelphia and it is different every year. Half of the time in Philadelphia there is a last frost after March 15 so make sure that you are prepared to cover your gladiolus if you have one of those late frosts.

USDA Zone Info for Philadelphia

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

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

Plants to Grow in Philadelphia

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