One of the first steps you take when you are figuring out your gardening schedule is find your USDA Zone info. 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 a good idea to plant tall phlox is to use the USDA zone info for Tomball.

Planting Calendar for Tall Phlox

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

Tall Phlox do ok in some cold which tells us that you can plant them a little earlier in the year than other plants that might not handle the cold.

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

Last Frost Date

In Tomball the average date of last frost happens on February 15. It might get as low as 20°F during the coldest months of winter.

Keep in mind that USDA zone info for Tomball is not always accurate and the actual date of last frost changes 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 tall phlox in the event of 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.