Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A way of estimating when it's possible to plant delphinium is to look at the USDA zone info for Port Isabel.

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.

Delphinium are barely cold tolerant which means that you can get them planted just a bit earlier than other plants that might not handle the cold.

The earliest that you can plant delphinium in Port Isabel 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. You probably don't want to wait any later than that or else your delphinium may not have a chance to really do well. You can get started a little bit earlier by starting your delphinium indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on January 31 in Port Isabel. It might get as low as 30°F during the coldest months of winter.

Since the USDA zone info for Port Isabel may not be accurate from year to year the actual date of last frost is different every year. Half of the time in Port Isabel there is a last frost after January 31 so make sure that you are ready to cover your delphinium if you have one of those late frosts.

USDA Zone Info for Port Isabel

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in Port Isabel

You may be interested in your other planting guides for Port Isabel.