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

You can figure out when it's a good idea to plant columbine in Tomball by reviewing the USDA zone info.

Planting Calendar for Columbine

Frost tolerance for columbine:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

You can plant columbine a little earlier in the year because they are moderately cold tolerant.

The earliest that you can plant columbine in Tomball is January. However, you really should wait until February if you don't want to take any chances.

The last month that you can plant columbine and expect a good harvest is probably October. You probably don't want to wait any later than that or else your columbine may not have a chance to fully mature. If you are starting your columbine indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

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

Remember that USDA zone info for Tomball is not always accurate and the actual date of last frost can change quite a bit from year to year. Half of the time in Tomball you get surprised by a frost after February 15 so make sure that you are prepared to cover your columbine in the event of a 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.