06/01/2026
You may have heard about the Turfgrass Water Conservation Alliance (TWCA) and its qualifications for drought-tolerance, but what does it actually take for a grass to earn the seal? See below to learn what our grasses go through to meet the standard.
1. Multi-Site, Multi-Year Trails:
Grass varieties are tested at different locations over multiple years. To qualify, cultivars must meet or exceed the drought-tolerance standard for at least two years.
2. Controlled Drought Testing:
- Drought Trials: Grass is grown under controlled water stress until 25% green cover remains.
- Low-Maintenence Trials: Grass is grown with minimal fertilizer and no pesticides, plus a drought cycle ensure performance under real-world conditions.
3. Standards & Experimental Layout:
- Six Standard Entries. Each trial includes six standard cultivars--two Drought tolerant, two Drought susceptible, and two commercial cultivars.
- Single Species Trials evaluate one grass species at a time to eliminate species-level differences
4. Objective Data Collection:
Digital Image Analysis (DIA): TWCA cooperators use light boxes to photograph plots at regular intervals. DIA software calculates percent green cover from RGB values in each image. Trails continue until plots drop below 25% green cover.
5. Independent Review:
Results are analyzed by university researchers who decide which cultivars earn TWCA qualification.
As water becomes increasingly limited in our region, choosing drought-tolerant grass varieties is more important than ever. Learn more at tgwca.org.