One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A common way of figuring out when it's a good idea to plant four-o-clock flower is to use the USDA zone info for Tomball.

Planting Calendar for Four-o-clock flower

Frost tolerance for four-o-clock flower:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Four-o-clock flower require warm weather which tells us that you really should wait until it warms up after the last frost before you can plant them.

The earliest that you can plant four-o-clock flower 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 four-o-clock flower and expect a good harvest is probably September. Any later than that and your four-o-clock flower may not have a chance to really do well. You can get started a couple of weeks earlier by starting your four-o-clock flower indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on February 15 in Tomball. You should expect an average low temperature of 20°F in the coldest months of winter.

Always keep in mind that USDA zone info for Tomball is an average and the actual date of last frost will vary from year to year. Since half of the time in Tomball last frost occurs after February 15 be ready to protect your four-o-clock flower 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.