The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In South Houston you can figure out when you can plant watercress by looking at the USDA zone info.

Planting Calendar for Watercress

Frost tolerance for watercress:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Watercress tend to make it in some cold which means that you can plant them just a tiny bit earlier in the year than more sensitive plants.

The earliest that you can plant watercress in South Houston is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant watercress and expect a good harvest is probably September. Any later than that and your watercress may not have a chance to really do well. You can get started a little bit earlier by starting your watercress indoors.

Last Frost Date

On average the last frost is on February 15 in South Houston. It might get as low as 20°F during the coldest months of winter.

Since the USDA zone info for South Houston may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in South Houston there is a last frost after February 15 so make sure that you are ready to cover your watercress if you have one of those late frosts.

USDA Zone Info for South Houston

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 South Houston

You may be interested in your other planting guides for South Houston.