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.

You should be able to figure out when it's a good idea to plant dahlias by looking at the USDA zone info for Del Rio.

Planting Calendar for Dahlias

Frost tolerance for dahlias:	Not tolerant of frost.
When to plant:	After the last frost.

You really shouldn't plant dahlias until after the last frost when the weather gets warmer because they do not do well in cold weather.

The earliest that you can plant dahlias in Del Rio 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 dahlias and expect a good harvest is probably September. Any later than that and your dahlias may not have a chance to grow to maturity. If you are starting your dahlias indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average the last frost is on February 15 in Del Rio. In the coldest months of winter you should expect an average low temperature of 20°F.

Just be sure to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Del Rio and it can change quite a bit from year to year. Half of the time in Del Rio you get surprised by a frost after February 15 so be sure to be ready to protect your dahlias if you have a surprise late frost.

USDA Zone Info for Del Rio

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 Del Rio

You may be interested in your other planting guides for Del Rio.