Large grass seed mats—also called seed blankets or erosion-control blankets—hold seed in place while it germinates and can reduce washout on slopes or exposed soil. If your mat has been stored in a roll, careful handling and correct placement help prevent tangles, gaps, and damage to the seed. Before starting, check the product label for its planting instructions, coverage, and recommended anchoring method; seed mixes and mat materials vary.
What You’ll Need
- Grass seed mat roll suited to your site and climate
- Garden rake, shovel, and hand trowel
- Measuring tape and utility knife or sturdy scissors
- Biodegradable landscape staples or stakes, in the number and pattern specified by the manufacturer
- Garden hose with a gentle spray nozzle
- Compost or topsoil, if needed to improve the prepared soil
- Work gloves; eye protection if cutting stiff or wire-reinforced material
Step-by-Step
- Choose a suitable time and check the site. Install when the soil is workable and heavy rain, frost, or extreme heat is not expected immediately. Follow the seed maker’s seasonal guidance for your region. Identify buried utilities before driving stakes, and avoid installing over a surface that is frozen, waterlogged, or actively eroding.
- Measure the area and plan the layout. Measure the length and width to estimate how many rolls you need. Plan to run each strip from the top of a slope toward the bottom, rather than across it, so water is less likely to catch an exposed edge. On flat ground, arrange strips to minimize awkward narrow pieces. Check the label for required overlaps; do not assume that every product uses the same seam width.
- Prepare the ground. Remove weeds, stones, sticks, and old turf. Loosen compacted soil with a rake or cultivator, then break up large clods and fill depressions that could collect water. Grade the surface smoothly without creating a steep, loose slope. Mix in a modest amount of suitable compost or topsoil if the ground needs improvement, and rake it level.
- Seed bare soil if the product requires it. Some mats contain seed; others are blankets intended to cover seed you spread separately. Read the packaging before adding anything. If seeding separately, use the recommended grass type and rate, distribute seed evenly, and lightly rake it into contact with the soil. Avoid burying seed deeply unless the product directions say to do so.
- Unroll the mat carefully. Place the roll at the intended starting edge and unroll it in the planned direction, keeping the material in contact with the ground. Ask another person to guide a large or heavy roll. Do not drag it across sharp rocks or pull hard on the fabric, as this can stretch, tear, or displace seed. If the roll is tightly wound, loosen it gradually rather than letting it spring open.
- Lay each strip flat. Smooth wrinkles and press the mat down so it touches the soil across its full width. Keep adjacent edges aligned, with the overlap specified on the package. On slopes, position the uphill edge as directed by the manufacturer and make sure water cannot run beneath an unsecured edge. Cut around paths or planting beds with scissors or a utility knife, keeping fingers clear of the blade.
- Secure the mat. Anchor the edges, seams, and field of each strip using the recommended staple type and spacing. Push staples fully into the soil so their tops hold the mat without leaving it loose, but do not tear the material. Use extra anchors where the ground is exposed to wind, runoff, or foot traffic, while following the product’s installation pattern. Never rely on a few staples at the corners alone.
- Water gently and inspect. Apply a light, even spray until the soil beneath the mat is moist. Avoid a strong jet that could move the mat, wash seed away, or expose soil. Walk the perimeter and check seams, cut edges, and slope transitions. Re-secure any lifted sections and confirm that water can drain without pooling.
- Maintain the site during establishment. Keep the soil consistently moist but not saturated, following the seed label for watering frequency. Protect the area from pets, mowing, and unnecessary foot traffic. Once grass is established, follow the product instructions about whether the mat should remain to biodegrade or be removed; many biodegradable blankets are designed to stay in place.
Common Mistakes
- Installing over poor ground: Weeds, large clods, and hollows prevent good contact and can leave seed uncovered. Prepare and level the surface first.
- Choosing the wrong mat: A thin seed mat may not be suitable for a steep bank or fast-moving runoff. Match the product to the slope and erosion risk, and seek site-specific advice for severe erosion.
- Leaving loose seams or edges: Wind and water can get underneath and lift the blanket. Overlap and staple it according to the label.
- Adding seed without checking: Seed may already be embedded in the mat. Extra seed can create crowded growth and waste; confirm the product type before sowing.
- Watering too forcefully: Strong spray can dislodge seed or shift the roll. Use a gentle shower and check the soil moisture beneath the mat.
- Cutting or stretching the mat carelessly: Rough handling creates gaps and weak points. Make clean cuts and avoid pulling the material taut over uneven ground.
Tips
- Keep the roll dry and shaded before installation, and check its label for storage limits. Do not leave it exposed to rain or sun longer than necessary.
- Set out the rolls before cutting so you can confirm the layout and overlaps. Save offcuts for small bare patches if the product permits.
- On slopes, work from the top down where practical, keeping each strip straight and securely anchored as you go.
- Take photos after installation and note the watering schedule. This makes it easier to spot shifting or missed patches during follow-up checks.
Troubleshooting
- The roll keeps springing open: Keep it partly rolled while positioning, or have a helper hold the loose end. Unroll a manageable section at a time and anchor it as directed.
- The mat lifts or slides: Reposition it while the soil is still workable, restore the required overlap, and add anchors according to the package pattern. If runoff is cutting beneath it, address the drainage source rather than only adding staples.
- Water pools on top: Check for low spots, wrinkles, or a blocked drainage path. If safe, lift the affected portion, smooth and regrade the soil, then lay and secure the mat again.
- Seed is washing out or showing through: Reduce watering pressure, improve soil contact, and repair gaps with compatible material. For continuing washout, the site may need a different erosion-control product or professional assessment.
- Germination is patchy: Check that the seed is suited to the season, the soil has stayed moist, and the mat has not dried out or shifted. Wait the germination period on the seed label; reseed bare spots at its recommended rate if needed.
Frequently Asked Questions
Which way should I unroll a grass seed mat on a slope?
Usually from the top of the slope toward the bottom, with strips running downhill. Follow the product’s directions for edge placement and overlap.
Do I need to put grass seed under the mat?
Only if the blanket is not pre-seeded and its instructions call for separate seeding. Check the packaging before spreading seed.
How much should the strips overlap?
Use the width specified by the manufacturer. Overlap requirements differ by mat design, slope, and intended use.
How many staples does a large mat need?
There is no single reliable number. Use the recommended staple spacing and pattern on the label, with secure seams and edges.
Can I walk or mow over the mat?
Avoid walking on it except for necessary installation and checks. Do not mow until the grass is established and the product instructions allow it.
Should I remove the mat after the grass grows?
Many biodegradable mats are intended to break down in place. Remove a mat only if its label says to; pulling it up too early can damage young grass.
Large Grass Seed Mats: How to Roll, Lay, and Secure Them