TWCA helps preserve the benefits of turfgrass while reducing water use. These FAQs guide homeowners, landscapers, municipalities, and industry professionals on TWCA’s mission, programs, and how to select and maintain drought-tolerant turfgrass. General lawn care FAQs at the bottom.
About TWCA
What is TWCA?
TWCA is a non-profit that tests and promotes turfgrass varieties proven to use up to 40% less water.
What is drought-tolerant turfgrass and why does it matter?
It’s grass bred to stay green with less water, saving resources and meeting regulations like California’s MWELO.
How does TWCA qualify turfgrass cultivars?
Grasses go through multi-year, multi-site drought trials, with independent data analysis. Only top performers earn TWCA Qualification.
How much water can I save with TWCA-qualified turf?
Use up to 40% less water compared to standard turf.
Where can I find TWCA-qualified seed or sod?
Visit TWCA’s Qualified Grasses page to search by species and region.
Using Drought-Tolerant Turf
How should I water drought-tolerant turf?
After lawn is fully established, water deeply once or twice a week early in the morning. Adjust for rainfall and extreme heat.
What are H2O Budgets?
A free TWCA tool that calculates water budgets for landscapes to help meet local code requirements.
What is Turf Trade?
A program that helps replace high-water-use turf with drought-tolerant varieties, saving millions of gallons of water annually.
Membership & Participation
Who can become a TWCA member?
Seed producers, sod farms, cities, universities, and industry partners. Members get research data, marketing support, and trial participation.
How does TWCA support landscape codes like MWELO?
By providing plant factors for qualified turfgrasses so designers can stay within water budgets while keeping green space.
General Lawn Care
How often should I mow?
Mow when grass is 3–4 inches tall, cutting to 2–3 inches and never removing more than one-third of the blade.
Should I fertilize drought-tolerant grass differently?
Yes—use moderate, slow-release nitrogen in spring and fall. Avoid over-fertilizing to keep water needs low.
What about weeds and pests?
Dense turf prevents weeds naturally. Use targeted weed and pest control as needed to protect soil and water health.
Choosing the Right Grass Seed
What’s the difference between cool‑season and warm‑season grasses?
Cool‑season grasses (e.g., Kentucky bluegrass, tall fescue, ryegrass, fine fescue) grow best in spring and fall, stay green in cool weather and may go dormant in summer heat. Warm‑season grasses (e.g., Bermuda, St. Augustine, zoysia) thrive in hot summers and may go dormant over winter. Choose according to your climate—northern lawns usually need cool‑season types, while deep south lawns need warm‑season varieties.
How do I choose the right grass seed for my region?
Pick seed based on your climate and site conditions. In northern and transition regions, cool‑season grasses provide year‑round color; in hot southern areas, warm‑season grasses tolerate heat and drought. Also consider shade (fine fescues for shade, tall fescue for sun). Avoid bargain seed mixes that contain annual ryegrass or weed seeds. Use TWCA Seed and Sod Supplier Map to find TWCA Qualified blends.
What do “blend” and “mixture” mean on the label?
A blend combines two or more cultivars of the same species (e.g., several cultivars of tall fescue); a mixture combines different species (e.g., bluegrass plus ryegrass). Blends improve disease resistance and uniformity, while mixtures increase adaptability to varied conditions such as sun and shade.
Planting & Establishment
When is the best time to plant grass seed?
For cool‑season lawns, late summer/early fall (mid‑August to mid‑September) is ideal because warm soil and cooler air promote quick germination and there’s less weed competition. Spring seeding is a secondary option but may face more weeds. Warm‑season grasses are typically seeded in late spring or early summer when soil temperatures reach 65–70 °F.
How much seed do I need per square foot?
Typical rates: 6–8 lb of tall fescue seed or 2–3 lb of Kentucky bluegrass seed per 1,000 sq ft. Rates are lower when overseeding an existing lawn (about half the new‑seed rate). Use our Seed Calculator to measure exactly how much you need.
Do I need to prepare my soil first?
Yes—good soil preparation is key. Remove debris, grade the area, and incorporate 4–6 inches of quality topsoil or compost. A soil test will tell you if lime or fertilizer is needed; if you skip testing, apply a starter fertilizer (e.g., 20‑5‑10) at 5 lb per 1,000 sq ft.
Should I cover the seed with straw or mulch?
Lightly raking seed into the soil improves contact, but don’t bury it—grass seed needs light to germinate. A thin layer of weed‑free straw, compost or mulch helps retain moisture and protect seed; however, research shows frequent irrigation can make mulch optional. Avoid thick mulch layers that smother seedlings.
Watering & Fertilization
How often should I water new seed?
Keep the top inch of soil consistently moist. Water lightly multiple times per day until seedlings are 1–2 inches tall, then reduce frequency and water more deeply to encourage deeper roots. Avoid puddling or letting the seed dry out.
When should I fertilize a new lawn?
Apply a starter fertilizer at seeding; a good ratio is roughly 1:1 or 1:1.5 nitrogen to phosphorus (e.g., 18‑24‑6). Do not exceed 1 lb of nitrogen and about 1–1.5 lb of phosphate per 1,000 sq ft. About six weeks after germination, apply another light dose of nitrogen (≈1 lb N/1,000 sq ft).
What kind of fertilizer should I use?
Starter fertilizers promote root development and early growth; look for N‑P‑K ratios with equal or slightly more phosphorus. Once established, cool‑season lawns need 4–6 lb of nitrogen per 1,000 sq ft per year, applied in several small doses. Always follow soil‑test recommendations and local regulations.
Lawn Care & Maintenance
When can I mow after seeding?
Begin mowing when new grass reaches about 3 inches tall and has been dry for a few hours. Cut back to 2–2.5 inches using a sharp blade, removing no more than one‑third of the leaf height. Early mowing encourages tillering (thickening) and prevents seedlings from falling over.
How do I prevent weeds in a new lawn?
Seed at the proper time (late summer for cool‑season grasses) to reduce weed pressure. Maintain a dense, healthy lawn—thick turf crowds out weeds. Most weed‑control herbicides should not be applied until the new grass has been mowed 3–4 times; wait 30 days after herbicide applications before seeding.
How often should I fertilize or overseed an established lawn?
Cool‑season lawns are typically fertilized four times per year with 0.5–1 lb nitrogen per 1,000 sq ft each application. Overseed thin areas in late summer/early fall; keep seedbed moist and fertilize with 1 lb nitrogen per 1,000 sq ft about six weeks after germination.
Troubleshooting & Common Problems
Why didn’t my seed germinate?
Common causes include improper soil prep, wrong timing (too hot or too cold), soil temp too low, planting depth, and insufficient moisture. Check these factors and try again at the recommended time.
What should I do about bare spots?
For patches, remove some dead grass, mix TWCA Qualified seed with a little soil or compost, and lightly rake for good seed‑to‑soil contact. Keep the spot moist until seedlings establish; wait to mow until the new grass is about 4 inches tall.
How do I fix yellow or thin grass?
Pale green or yellow lawns are often due to iron or nitrogen deficiency; severe cases show yellow streaks along the veins. Apply a fertilizer containing nitrogen, and if soil tests indicate, supplement with iron. Thin lawns may result from soil compaction, poor drainage or insufficient fertility—aerate compacted soil, overseed in late summer, and follow a regular fertilizing and watering schedule. Drought stress can also cause brown patches; deep, infrequent watering and raising the mowing height help cool‑season grasses survive dry periods.