1. Clear the area
- Use a shovel or sod cutter to remove your old lawn and any weeds that might be present.
- Remove any large stones or wood debris from the soil; the wood can promote fungus diseases.
2. Grade the subsoil
- Create at least a 2% grade away from buildings, driveways, and walks to ensure proper surface drainage. To calculate the depth of a 2% grade:
- measure the distance from your house to the sidewalk (e.g., 15 m)
- multiply this number by .02 (e.g., 15 X .02 = .3)
- create a drop that equals your answer (over 15 m, the slope would drop 30 cm from the house to the sidewalk.)
- consider terracing your yard if you have a 25% slope or more since these yards are difficult to mow and prone to soil erosion.
- As you grade your subsoil, stockpile excess topsoil to the side of your yard. Break up the top 5 cm of your soil to eliminate the hardpan layer; however, do not change your grade while doing so.
3. Add topsoil
- Add a 15 to 20 cm layer of topsoil over the subsoil.
- Mix in a 5 cm layer of amendment (compost, peat moss, manure.)
4. Prepare your final surface
- Ensure your final surface has the same grade as your subsoil and should be 1.2 to 2.5 cm below the level of sidewalks and driveways.
- Remove any depressions or valleys on the surface by raking the surface or by dragging a ladder or plank in various directions.
- Roll the surface. You can rent a roller, weighted with water, from your local rental shop or DYI store.
5. Control weeds
Allow any weeds in your soil to germinate by watering the soil and waiting a week.
If a flush of weeds appear:
- Annual weeds – control annual weeds by rototilling or hoeing. Do not change the grade of your lawn when removing these weeds.
- Perennial weeds – control perennial weeds through soil solarisation or glyphosate. Wait at least 10 days before seeding or sodding if you use glyphosate. Glyphosate is inactivated by soil so you do not have to worry about residues killing your new grass after this period.
If possible, water your soil and wait another week to allow any residual weeds to appear. If they do, control the weeds as indicated above.
6. Install underground irrigation (if desired)
It’s easier to install underground irrigation systems before seeding or laying your sod.
Draw a map of your underground water lines in case you need to locate them in the future.
7. Fertilize and reset final grade
Just before seeding, apply a high phosporus fertilizer (1-2-0 or 1-3-0 ratio) to help grass root.
Double check your area’s grade; if it has changed, reset the grade following the guidelines under step 4.