Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

It's a good idea to estimate when it's possible to plant dahlias by using the USDA zone info for Tomball.

Planting Calendar for Dahlias

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

You can not plant dahlias until after all chance of frost has passed because they do not do well in cold weather.

The earliest that you can plant dahlias in Tomball 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. If you wait any later than that and your dahlias may not have a chance to really do well. You can get started a few weeks earlier by starting your dahlias indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on February 15 in Tomball. In the coldest months of winter you can 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 Tomball and it can change quite a bit from year to year. Half of the time in Tomball you get a frost after February 15 so make sure that you are ready to protect your dahlias if you have a surprise late frost.

USDA Zone Info for Tomball

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 Tomball

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