🌱 Guide to Prepare Soil for a New Hydroseed Lawn
A great lawn begins long before the first spray of hydroseed. Think of it like prepping a fresh garden bed—it needs proper planning, patience, and preparation.
(This data is based on jobs primarily in king-county, snohomish-county, pierce-county, and thurston-county in the last few years...)
Download our Hydroseeding Prep Guide
đź“Ź 1. Measure the Area
Before you begin, measure the total square footage of the area you want hydroseeded. This helps estimate the cost of materials, labor, and seed mix, and helps avoid over- or under-prepping.
🧹 2. Clear the Area
Remove all existing vegetation:
- Use a non-selective herbicide like RoundUp to kill weeds and grass at the root.
- Wait 7–15 days (or per label) after spraying before disturbing the soil.
- Weed whack or mow the area down low once vegetation is fully dead.
Eliminate all debris:
- Remove rocks larger than an egg, sticks, roots, and any stumps.
- Clear the surface to bare, native soil.
🪨 3. Assess and Amend the Soil
Soil is made up of varying amounts of sand, silt, and clay. The best base for hydroseeding is loamy soil—crumbly, aerated, and rich in organic matter.
🔬 Test the Soil (Optional, but recommended)
- Perform a soil test to check pH and nutrient levels.
- Lawns in the Pacific Northwest often need dolomitic lime to reduce acidity.
đź› Amend as Needed:
- Add 4–6 inches of weed-free, high-quality topsoil
- Blend in organic matter (composted manure, peat moss, etc.)
- A suggested ratio is 1–2" of compost mixed into the top 5–6" of soil
- Include lime and a starter fertilizer high in phosphorus
🌀 4. Till & Blend the Soil
Depth matters:
- Till the new topsoil and amendments into the native soil to a depth of 5–6 inches.
- Avoid tilling deeper than 6 inches to prevent bringing up new weed seeds or buried debris.
Tip: If your soil is excessively rocky or your yard is large, consider hiring a contractor with a tractor-tiller or roto-darian.
🪵 5. Grade & Level
Create a smooth, even base:
- Grade for drainage—ensure the soil slopes away from structures to avoid pooling.
- Fill in low spots and lightly compact overly fluffy areas with a roller (half-full with water).
- Rake thoroughly to smooth out ruts or ridges, especially near fences, pathways, and beds.
- Roll and re-rake the surface the day before hydroseeding to break any crust.
đź’§ 6. Water Management & Irrigation
Proper irrigation is critical:
- Install and test your sprinkler system before hydroseeding.
- Ensure full coverage, and check for low-pressure zones or broken heads.
- Avoid standing water or overly dry patches during initial lawn establishment.
đźš© 7. Mark the Area
Before the hydroseed crew arrives:
- Use spray paint, flags, or stakes to mark the boundaries of the lawn area.
- Indicate obstacles or "no-spray" zones clearly to ensure clean lines and full coverage.
🧪 Special Notes for Unique Soil Conditions
| Condition | Recommended Prep |
|---|---|
| Hard Clay / Compacted Soil | Add at least 4" of sandy loam. Don't waste time amending heavy clay. |
| Glacial Till / Rocky Soil | Import 6" of quality sandy loam. Avoid tilling—use top dressing only. |
| Overgrown/Trashed Lawns | Best to sod cut and start over. RoundUp + tilling isn't worth the effort over large areas. |
| Wet / Soggy Lawns | Regrade to allow runoff or install catch basins. Add winter mix (at least 50% sand) to raise grade above water table by 6". |
| Rototilled / Excavated Soil | Ready for hydroseed—just lightly rake, level, and roll before spraying. |
| Heavily Vegetated Soil | Remove vegetation, retain usable topsoil, and rake/roll to prepare. |
âś… Final Checklist Before Hydroseeding
🎯 Where Hydroseeding Begins
Once your soil is prepped, the hydroseed application is a fast, effective way to start your new lawn. Proper preparation can save you time, money, and headaches—and give your grass the lush, vibrant start it deserves.
🌿 Prep well, seed once. Enjoy your perfect lawn for years to come.
