The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Roma you can determine when to plant delphinium by checking out the USDA zone info.

Planting Calendar for Delphinium

Frost tolerance for delphinium:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

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

The earliest that you can plant delphinium in Roma 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 delphinium and expect a good harvest is probably September. If you wait any later than that and your delphinium may not have a chance to really do well. Starting your delphinium indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average all chance of frost has passed is on February 15 in Roma. In the coldest months of winter you can expect an average low temperature of 25°F.

It's important to remember that the actual date of last frost is an average because it is based on the USDA zone info for Roma and it can change quite a bit from year to year. Since half of the time in Roma last frost occurs after February 15 be ready to cover your delphinium in the event of a late frost.

USDA Zone Info for Roma

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 Roma

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