TWCA Qualification & Trialing Parameters
TWCA ensures that only the most water-efficient turfgrasses earn the TWCA Qualified seal. Our program is rigorous, science-based, and completely independent — so you can trust that TWCA-qualified grasses really do save water.
How Grasses Qualify
1. Multi-Year, Multi-Site Trials
Entries are tested across multiple locations and years. Cultivars must meet or exceed the drought‑tolerance standard at all locations for at least two years to qualify.
2. Controlled Drought Testing
TWCA uses two trial types:
- Drought Trials: Grass is grown under controlled water stress until 25% green cover remains.
- Low-Maintenance Trials: Grass is grown with minimal fertilizer and no pesticides, plus a drought cycle, to ensure it performs well under tough, real-world conditions.
3. Standards and Experimental Layout
- Six standard entries: Each trial includes six standard cultivars—two drought‑tolerant, two drought‑susceptible, and two commercial cultivars from the marketplace. These standards allow TWCA to benchmark performance and ensure results are repeatable.
- Single‑species focus: Trials evaluate one turfgrass species at a time to eliminate species‑level differences.
4. Objective Data Collection
Digital Image Analysis (DIA): TWCA cooperators use light boxes to take standardized photographs of each plot at regular intervals. DIA software calculates percent green cover from RGB values in each image. Trials continue until plots drop below 25 % green cover.
5. Independent Review
Results are analyzed by university researchers who decide which cultivars earn TWCA qualification.
Requirements for the TWCA Seal
- Consistent Performance: Must meet drought-tolerance standards at all sites for at least two years.
- Objective Proof: Qualification is based on data, not opinion.
- Peer Review: All results are reviewed by independent scientists.
- Re-Qualification: Products must re-qualify periodically against higher standards.
- Minimum Composition: Products with the TWCA seal must contain at least 70% qualified grass seed.
Proven Water Savings For All
The TWCA qualification and trialing process provides homeowners, landscapers, sod farms, and all turfgrass managers with confidence that TWCA‑qualified cultivars deliver proven water savings without sacrificing turf quality.
